docs: heavy editing to make this happy with latest wikibridge.

The public headers saw lots of cleanups, backporting from SDL3 docs, and
merging with the wiki.

The markdown files in docs/README-*.md were converted to Unix endlines.

include/SDL_keyboard.h

@@ -40,14 +40,15 @@ extern "C" {
 #endif
 
 /**
- *  \brief The SDL keysym structure, used in key events.
+ * The SDL keysym structure, used in key events.
  *
- *  \note  If you are looking for translated character input, see the ::SDL_TEXTINPUT event.
+ * If you are looking for translated character input, see the SDL_TEXTINPUT
+ * event.
  */
 typedef struct SDL_Keysym
 {
-    SDL_Scancode scancode;      /**< SDL physical key code - see ::SDL_Scancode for details */
-    SDL_Keycode sym;            /**< SDL virtual key code - see ::SDL_Keycode for details */
+    SDL_Scancode scancode;      /**< SDL physical key code - see SDL_Scancode for details */
+    SDL_Keycode sym;            /**< SDL virtual key code - see SDL_Keycode for details */
     Uint16 mod;                 /**< current key modifiers */
     Uint32 unused;
 } SDL_Keysym;