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_version.h

@@ -40,10 +40,9 @@ extern "C" {
  * Information about the version of SDL in use.
  *
  * Represents the library's version as three levels: major revision
- * (increments with massive changes, additions, and enhancements),
- * minor revision (increments with backwards-compatible changes to the
- * major revision), and patchlevel (increments with fixes to the minor
- * revision).
+ * (increments with massive changes, additions, and enhancements), minor
+ * revision (increments with backwards-compatible changes to the major
+ * revision), and patchlevel (increments with fixes to the minor revision).
  *
  * \sa SDL_VERSION
  * \sa SDL_GetVersion
@@ -64,12 +63,11 @@ typedef struct SDL_version
 /**
  * Macro to determine SDL version program was compiled against.
  *
- * This macro fills in a SDL_version structure with the version of the
- * library you compiled against. This is determined by what header the
- * compiler uses. Note that if you dynamically linked the library, you might
- * have a slightly newer or older version at runtime. That version can be
- * determined with SDL_GetVersion(), which, unlike SDL_VERSION(),
- * is not a macro.
+ * This macro fills in a SDL_version structure with the version of the library
+ * you compiled against. This is determined by what header the compiler uses.
+ * Note that if you dynamically linked the library, you might have a slightly
+ * newer or older version at runtime. That version can be determined with
+ * SDL_GetVersion(), which, unlike SDL_VERSION(), is not a macro.
  *
  * \param x A pointer to a SDL_version struct to initialize.
  *
@@ -85,37 +83,40 @@ typedef struct SDL_version
 
 /* TODO: Remove this whole block in SDL 3 */
 #if SDL_MAJOR_VERSION < 3
+
 /**
- *  This macro turns the version numbers into a numeric value:
- *  \verbatim
-    (1,2,3) -> (1203)
-    \endverbatim
+ * This macro turns the version numbers into a numeric value:
  *
- *  This assumes that there will never be more than 100 patchlevels.
+ * ```
+ * (1,2,3) -> (1203)
+ * ```
  *
- *  In versions higher than 2.9.0, the minor version overflows into
- *  the thousands digit: for example, 2.23.0 is encoded as 4300,
- *  and 2.255.99 would be encoded as 25799.
- *  This macro will not be available in SDL 3.x.
+ * This assumes that there will never be more than 100 patchlevels.
+ *
+ * In versions higher than 2.9.0, the minor version overflows into the
+ * thousands digit: for example, 2.23.0 is encoded as 4300, and 2.255.99 would
+ * be encoded as 25799.
+ *
+ * This macro will not be available in SDL 3.x.
  */
 #define SDL_VERSIONNUM(X, Y, Z)                     \
     ((X)*1000 + (Y)*100 + (Z))
 
 /**
- *  This is the version number macro for the current SDL version.
+ * This is the version number macro for the current SDL version.
  *
- *  In versions higher than 2.9.0, the minor version overflows into
- *  the thousands digit: for example, 2.23.0 is encoded as 4300.
- *  This macro will not be available in SDL 3.x.
+ * In versions higher than 2.9.0, the minor version overflows into the
+ * thousands digit: for example, 2.23.0 is encoded as 4300. This macro will
+ * not be available in SDL 3.x.
  *
- *  Deprecated, use SDL_VERSION_ATLEAST or SDL_VERSION instead.
+ * Deprecated, use SDL_VERSION_ATLEAST or SDL_VERSION instead.
  */
 #define SDL_COMPILEDVERSION \
     SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL)
 #endif /* SDL_MAJOR_VERSION < 3 */
 
 /**
- *  This macro will evaluate to true if compiled with SDL at least X.Y.Z.
+ * This macro will evaluate to true if compiled with SDL at least X.Y.Z.
  */
 #define SDL_VERSION_ATLEAST(X, Y, Z) \
     ((SDL_MAJOR_VERSION >= X) && \