patch 9.1.0322: filetype: some mail tools not recognized

Problem:  filetype: some mail tools not recognized
Solution: Detect '.mbsncrc' as conf, '.msmtprc' as msmtp
          and '.notmuch-config' as ini filetype
          (Shane-XB-Qian)

closes: #14533

Signed-off-by: shane.xb.qian <shane.qian@foxmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/filetype.vim

@@ -1396,6 +1396,9 @@ au BufNewFile,BufRead *.nb			setf mma
 " Maya Extension Language
 au BufNewFile,BufRead *.mel			setf mel
 
+" mbsync
+au BufNewFile,BufRead .mbsyncrc			setf conf
+
 " Mercurial (hg) commit file
 au BufNewFile,BufRead hg-editor-*.txt		setf hgcommit
 
@@ -1428,6 +1431,9 @@ au BufNewFile,BufRead *.mix,*.mixal		setf mix
 " MMIX or VMS makefile
 au BufNewFile,BufRead *.mms			call dist#ft#FTmms()
 
+" msmtp
+au BufNewFile,BufRead .msmtprc			setf msmtp
+
 " Symbian meta-makefile definition (MMP)
 au BufNewFile,BufRead *.mmp			setf mmp
 
@@ -1555,6 +1561,9 @@ au BufNewFile,BufRead *.mm			call dist#ft#FTmm()
 " Not Quite C
 au BufNewFile,BufRead *.nqc			setf nqc
 
+" notmuch
+au BufNewFile,BufRead .notmuch-config		setf dosini
+
 " NSE - Nmap Script Engine - uses Lua syntax
 au BufNewFile,BufRead *.nse			setf lua
 
@@ -3117,3 +3126,5 @@ endfunc
 " Restore 'cpoptions'
 let &cpo = s:cpo_save
 unlet s:cpo_save
+
+" vim: ts=8