Update wxStyledTextCtrl documentation

Table of contents is added to the documentation for wxSTC and the brief list of methods is broken into categories corresponding to this table. Documentation of several methods is rearranged and edited.

Closes #17803.

include/wx/stc/stc.h

@@ -3173,6 +3173,10 @@ public:
     // Get the weight of characters of a style.
     int StyleGetWeight(int style) const;
 
+    // Set the character set of the font in a style.
+    // Converts the Scintilla character set values to a wxFontEncoding.
+    void StyleSetCharacterSet(int style, int characterSet);
+
     // Set a style to be a hotspot or not.
     void StyleSetHotSpot(int style, bool hotspot);
 
@@ -3544,6 +3548,9 @@ public:
     // Draw the selection in normal style or with selection highlighted.
     void HideSelection(bool hide);
 
+    // Retrieve the point in the window where a position is displayed.
+    wxPoint PointFromPosition(int pos);
+
     // Retrieve the line containing a position.
     int LineFromPosition(int pos) const;
 
@@ -5042,10 +5049,6 @@ public:
                           wxFontEncoding encoding=wxFONTENCODING_DEFAULT);
 
 
-    // Set the character set of the font in a style.  Converts the Scintilla
-    // character set values to a wxFontEncoding.
-    void StyleSetCharacterSet(int style, int characterSet);
-
     // Set the font encoding to be used by a style.
     void StyleSetFontEncoding(int style, wxFontEncoding encoding);
 
@@ -5058,10 +5061,6 @@ public:
     void SetMargins(int left, int right);
 
 
-    // Retrieve the point in the window where a position is displayed.
-    wxPoint PointFromPosition(int pos);
-
-
     // Scroll enough to make the given line visible
     void ScrollToLine(int line);