Using direct links to https://wiki.libsdl.org/... break the offline version.

[Count-MHM]

First noticed this problem in CategoryKeyboard, CategoryKeycode, and CategoryScancode. But a quick search finds 2423 results. Which can't be fixed one by one in wiki.
Most of them are the legacy headers at the top of the wiki, which can be fixed using "find and replace".
Some like this source from SDL also links directly, which may need so modification after extracting documentation from source files.
Approximately 50 results need to be fixed manually, either in this repo or by changing how documentation inside files are handled.

[Count-MHM]

#757 #758 #759 are the pull requests I made before noticing how widespread this issue is.