wikiheaders: optionally generate a Quick Reference page.

Plus some fixes to SDL's headers this brought up.

.wikiheaders-options

@@ -21,3 +21,10 @@ manpageheaderfiletext = Defined in SDL3/%fname%
 # All SDL_test_* headers become undefined categories, everything else just converts like SDL_audio.h -> Audio
 # A handful of others we fix up in the header itself with /* WIKI CATEGORY: x */ comments.
 headercategoryeval = s/\ASDL_test_?.*?\.h\Z//; s/\ASDL_?(.*?)\.h\Z/$1/; ucfirst();
+
+quickrefenabled = 1
+quickrefcategoryorder = Init,Hints,Error,Version,Properties,Log,Video,Events,Keyboard,Mouse,Touch,Gamepad,Joystick,Haptic,Audio,Time,Timer,Render,SharedObject,Thread,Mutex,Atomic,Filesystem,IOStream,AsyncIO,Storage,Pixels,Surface,Blendmode,Rect,Camera,Clipboard,Dialog,GPU,Messagebox,Vulkan,Metal,Platform,Power,Sensor,Process,Bits,Endian,Assert,CPUInfo,Locale,System,Misc,GUID,Main,Stdinc
+quickreftitle = SDL3 API Quick Reference
+quickrefurl = https://libsdl.org/
+quickrefdesc = The latest version of this document can be found at https://wiki.libsdl.org/SDL3/QuickReference
+quickrefmacroregex = \A(SDL_PLATFORM_.*|SDL_Atomic...Ref|SDL_assert.*?|SDL_arraysize|SDL_Swap[BL]E\d\d|SDL_[a-z]+_cast)\Z