doc(Polar): Improve class main documentation

- Use the proper syntax to take advantage of Matlab formatting and links
in help.

- Add more details and reformulate some stuff.

+af_tools/@Polar/Polar.m

 classdef Polar
-    % POLAR  Class for polars and their manipulations.
-    %   The POLAR class is used to represent completely one or multiple polar curves related to a
-    %   single airfoil.
+    % POLAR Airfoil polars and some associated properties.
+    %   The Polar class is used to store an airfoil polars (cl, cd, cm values for different angles
+    %   of attacks, at different Reynolds and Mach numbers).
+    %   It can also contain some interesting extra properties such as the stall point, the zero-lift
+    %   points, the linear lift range. It is also possible to compute the extrapolation of the
+    %   polars over the complete range of angles of attack if needed.
     %
-    %   The class also implements quick shortcuts for the more generic functions of af_tools, such
-    %   as findcllinearrange, findstall or findzerolift.
+    % Note:
+    %   - One Polar object correspond to one Airfoil. The properties of the Polar object are
+    %     vectors/matrices whose the columns represent a single polar curve.
+    %   - The method 'loadpolar' can be used instead of the constructor to load a previously saved
+    %     polar object.
     % -----
     %
-    % Properties:
-    %   - airfoil  : Airfoil name
-    %   - reynolds : Rynolds number of each polar curve
-    %   - mach     : Mach number of each polar curve
-    %   - nCrit    : nCrit number of each polar curve
-    %   - aoa      : Angles of attack (one column per Reynolds)
-    %   - cl       : Lift coefficient (one row per aoa, one column per Reynolds)
-    %   - cd       : Drag coefficient (one row per aoa, one column per Reynolds)
-    %   - cm       : Moment coefficient (one row per aoa, one column per Reynolds)
+    % Polar properties:
+    %   reynolds - Rynolds number of each polar curve, [-]
+    %   mach     - Mach number of each polar curve, [-]
+    %   nCrit    - nCrit number of each polar curve, [-]
+    %   aoa      - Angles of attack (one column per Reynolds), [rad]
+    %   cl       - Lift coefficient (one row per aoa, one column per Reynolds), [-]
+    %   cd       - Drag coefficient (one row per aoa, one column per Reynolds), [-]
+    %   cm       - Moment coefficient (one row per aoa, one column per Reynolds), [-]
+    %   Ext      - Struct with the data of the extended polars
+    %   Stall    - Struct with the data of the stall point for each curve
+    %   Zero     - Struct with the data of the zero-lift point for each curve
+    %   Lin      - Struct with the data of the linear range each curve
     %
-    % Private properties (set by running the methods below):
-    %   - Ext   : Struct with the data of the extended polars
-    %   - Stall : Struct with the data of the stall point for each curve
-    %   - Zero  : Struct with the data of the zero-lift point for each curve
-    %   - Lin   : Struct with the data of the linear range each curve
+    % Polar methods:
+    %   Polar          - Constructor
+    %   loadpolar      - Load a polar from the MAT-file
+    %   extendpolar    - Extend polar curves over [-pi, pi]
+    %   findstall      - Find stall point
+    %   findzerolift   - Find zero-lift point
+    %   findcllinrange - Find lift curve linear range
+    %   analyze        - Runs the above three functions
+    %   plotpolars     - Plot the polars
     %
-    % Methods (consult the help of each method with "help af_tools.Polar.<method>"):
-    %   - loadpolar      : Load a polar from the MAT-file
-    %   - extendpolar    : Extend polar curves over [-pi, pi]
-    %   - findstall      : Find stall point
-    %   - findzerolift   : Find zero-lift point
-    %   - findcllinrange : Find lift curve linear range
-    %   - analyse        : Runs the above three functions
-    %   - plotpolars     : Plot the polars
+    % Polar constructor:
+    %   Pol = Polar() creates an empty object.
     %
+    %   Pol = Polar(reynolds, aoa, c_l) creates a polar object with only the lift coefficient data.
     %
-    % See also: af_tools.xf2mat.
+    %   Pol = Polar(reynolds, aoa, c_l, c_d, c_m) creates a polar object with only the lift and drag
+    %   coefficients data.
+    %
+    %   Pol = Polar(reynolds, aoa, c_l, c_d, c_m) creates a polar object with the data for the lift,
+    %   drag and moment coefficient.
+    %
+    % Constructor input:
+    %   reynolds : Rynolds number of each polar curve, [-]
+    %   aoa      : Angles of attack (one column per Reynolds), [rad]
+    %   cl       : Lift coefficient (one row per aoa, one column per Reynolds), [-]
+    %   cd       : Drag coefficient (one row per aoa, one column per Reynolds), [-]
+    %   cm       : Drag coefficient (one row per aoa, one column per Reynolds), [-]
+    %
+    % See also: af_tools.Airfoil, af_tools.xf2mat.
     %
     % <a href="https://gitlab.uliege.be/am-dept/matlab_airfoil_toolbox">Documentation (online)</a>
 
+    % TODO: make this class handle class, verify everything, simplfiy methods
     % -------------------------------------------
     % (c) Copyright 2022 University of Liege
     % Author: Thomas Lambert <t.lambert@uliege.be>
@@ -45,22 +67,22 @@ classdef Polar
     % Repo: https://gitlab.uliege.be/am-dept/matlab_airfoil_toolbox
     % Issues: https://gitlab.uliege.be/am-dept/matlab_airfoil_toolbox/-/issues
     % ----------------------------------------------------------------------------------------------
+
     properties
-        airfoil  (1, :) cell
-        reynolds (1, :) double {mustBeNonnegative}
-        mach     (1, :) double {mustBeNonnegative}
-        nCrit    (1, :) double {mustBeNonnegative}
-        aoa      (:, :) double {mustBeReal}
-        cl       (:, :) double {mustBeReal}
-        cd       (:, :) double {mustBeReal}
-        cm       (:, :) double {mustBeReal}
+        reynolds (1, :) double {mustBeNonnegative} % Rynolds number, [-]
+        mach     (1, :) double {mustBeNonnegative} % Mach number, [-]
+        nCrit    (1, :) double {mustBeNonnegative} % nCrit number, [-]
+        aoa      (:, :) double {mustBeReal} % Angles of attack, [rad]
+        cl       (:, :) double {mustBeReal} % Lift coefficient, [-]
+        cd       (:, :) double {mustBeReal} % Drag coefficient, [-]
+        cm       (:, :) double {mustBeReal} % Moment coefficient, [-]
     end
 
     properties (SetAccess = private)
-        Ext   = struct('aoa', [], 'cl', [], 'cd', [], 'cm', [])
-        Stall = struct('aoa', [], 'cl', [], 'cd', [])
-        Zero  = struct('aoa', [], 'cd', [])
-        Lin   = struct('slope', [], 'aoaRange', [],  'clRange', [])
+        Ext   = struct('aoa', [], 'cl', [], 'cd', [], 'cm', []) % Extended polar data
+        Stall = struct('aoa', [], 'cl', [], 'cd', []) % Stall point data
+        Zero  = struct('aoa', [], 'cd', []) % Zero-lift point data
+        Lin   = struct('slope', [], 'aoaRange', [],  'clRange', []) % Lift linear range data
     end
 
     % ----------------------------------------------------------------------------------------------
@@ -68,7 +90,11 @@ classdef Polar
 
         function self = Polar(reynolds, aoa, c_l, c_d, c_m)
             % POLAR Constructor for Polar object
-            %   Create a polar object with basic information.
+            %   Instantiate a polar object using basic information. See the main class help for
+            %   details about the constructor inputs.
+            %
+            %   It is also possible to populate the properties of the object based on a saved polar
+            %   using the Polar.loadpolar method.
             %
             % See also: af_tools.Polar.loadpolar
 
@@ -118,7 +144,7 @@ classdef Polar
         function self = findcllinrange(self)
             % FINDZEROLIFT  Find the linear range of the cl and its slope
             %
-            % See also: af_tools.findcllinrange.
+            % See also: af_tools.findcllinearrange.
 
             [self.Lin.clRange, self.Lin.aoaRange, self.Lin.slope] = ...
                 af_tools.findcllinearrange(self);
@@ -137,7 +163,7 @@ classdef Polar
         function self = analyze(self)
             % ANALYZE  Get all useful information from the polar curves at once
             %
-            % See also: af_tools.findstall, af_tools.findzerolift, af_tools.findcllinrange.
+            % See also: af_tools.findstall, af_tools.findzerolift, af_tools.findcllinearrange.
 
             self = findstall(self);
             self = findzerolift(self);