docs(filetype): add note about prefering explicit lists over pattern

runtime/doc/dev_vimpatch.txt

@@ -310,6 +310,11 @@ FILETYPE DETECTION                 *dev-vimpatch-filetype*
 Nvim's filetype detection behavior matches Vim, but is implemented as part of
 |vim.filetype| (see $VIMRUNTIME/lua/vim/filetype.lua).
 
+Prefer explicit filenames/extensions over patterns, especially for case
+insensitive matches (see https://github.com/neovim/neovim/pull/29800): >
+    "*[mM]akefile" regex -> "makefile", "Makefile" filenames
+    "*.js\c"       regex -> "js", "jS", "Js", "jS" extensions
+
 Pattern matching has several differences:
 - It is done using explicit Lua patterns (without implicit anchoring) instead
   of Vim regexes: >

runtime/lua/vim/filetype.lua

@@ -1896,6 +1896,8 @@ local detect_xkb = starsetf('xkb', { parent = '/usr/' })
 --- Vim regexes are converted into explicit Lua patterns (without implicit anchoring):
 --- '*/debian/changelog' -> '/debian/changelog$'
 --- '*/bind/db.*' -> '/bind/db%.'
+---
+--- See more info in `:h dev-vimpatch-filetype`.
 --- @type table<string,vim.filetype.mapping>
 local pattern = {
   -- BEGIN PATTERN