vim-patch:9.1.0592: runtime: filetype: Mediawiki files are not recognized

Problem:  filetype: Mediawiki files are not recognized
Solution: detect "*.mw" and "*.wiki" as mediawiki filetype,
          include basic syntax and filetype plugins.
          (AvidSeeker)

closes: vim/vim#15266

b5844104ab

Co-authored-by: AvidSeeker <avidseeker7@protonmail.com>

runtime/lua/vim/filetype.lua

@@ -698,6 +698,8 @@ local extension = {
   dm3 = 'maxima',
   dmt = 'maxima',
   wxm = 'maxima',
+  mw = 'mediawiki',
+  wiki = 'mediawiki',
   mel = 'mel',
   mmd = 'mermaid',
   mmdc = 'mermaid',