fix(ftplugin): source inherited Lua ftplugins

Problem:
Vimscript ftplugins that inherit a base ftplugin often use explicit
`runtime! ftplugin/foo.vim` patterns. This skips corresponding Lua
ftplugins, unlike top-level ftplugin loading.

Solution:
Use the existing `{vim,lua}` patterns for bang runtime imports while
preserving each call's current lookup breadth.

runtime/ftplugin/php.vim

@@ -24,7 +24,7 @@ else
 endif
 let s:match_words = ""
 
-runtime! ftplugin/html.vim ftplugin/html_*.vim ftplugin/html/*.vim
+runtime! ftplugin/html[.]{vim,lua} ftplugin/html_*.{vim,lua} ftplugin/html/*.{vim,lua}
 let b:did_ftplugin = 1
 
 " Override our defaults if these were set by an included ftplugin.