patch 8.2.4014: git and gitcommit file types not properly recognized

Problem:    Git and gitcommit file types not properly recognized.
Solution:   Adjust filetype detection. (Tim Pope, closes #9477)

runtime/filetype.vim

@@ -497,7 +497,7 @@ au BufNewFile,BufRead */debian/patches/*	call dist#ft#Dep3patch()
 " Diff files
 au BufNewFile,BufRead *.diff,*.rej		setf diff
 au BufNewFile,BufRead *.patch
-	\ if getline(1) =~ '^From [0-9a-f]\{40\} Mon Sep 17 00:00:00 2001$' |
+	\ if getline(1) =~# '^From [0-9a-f]\{40,\} Mon Sep 17 00:00:00 2001$' |
 	\   setf gitsendemail |
 	\ else |
 	\   setf diff |
@@ -676,6 +676,7 @@ autocmd BufRead,BufNewFile *.gift		setf gift
 
 " Git
 au BufNewFile,BufRead COMMIT_EDITMSG,MERGE_MSG,TAG_EDITMSG	setf gitcommit
+au BufNewFile,BufRead NOTES_EDITMSG,EDIT_DESCRIPTION		setf gitcommit
 au BufNewFile,BufRead *.git/config,.gitconfig,/etc/gitconfig	setf gitconfig
 au BufNewFile,BufRead */.config/git/config			setf gitconfig
 au BufNewFile,BufRead .gitmodules,*.git/modules/*/config	setf gitconfig
@@ -684,12 +685,8 @@ if !empty($XDG_CONFIG_HOME)
 endif
 au BufNewFile,BufRead git-rebase-todo		setf gitrebase
 au BufRead,BufNewFile .gitsendemail.msg.??????	setf gitsendemail
-au BufNewFile,BufRead .msg.[0-9]*
-      \ if getline(1) =~ '^From.*# This line is ignored.$' |
-      \   setf gitsendemail |
-      \ endif
 au BufNewFile,BufRead *.git/*
-      \ if getline(1) =~ '^\x\{40\}\>\|^ref: ' |
+      \ if getline(1) =~# '^\x\{40,\}\>\|^ref: ' |
       \   setf git |
       \ endif
 

runtime/scripts.vim

@@ -384,7 +384,7 @@ else
     set ft=scheme
 
   " Git output
-  elseif s:line1 =~# '^\(commit\|tree\|object\) \x\{40\}\>\|^tag \S\+$'
+  elseif s:line1 =~# '^\(commit\|tree\|object\) \x\{40,\}\>\|^tag \S\+$'
     set ft=git
 
    " Gprof (gnu profiler)