patch 9.1.0796: filetype: libtool files are not recognized

Problem:  filetype: libtool files are not recognized
Solution: detect '*.{lo,la,lai}' as sh filetype
          (Wu, Zhenyu)

closes: #15751

Signed-off-by: Wu, Zhenyu <wuzhenyu@ustc.edu>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/filetype.vim

@@ -570,6 +570,9 @@ au BufNewFile,BufRead *.dsp				call dist#ft#FTdsp()
 au BufNewFile,BufRead *.xcu,*.xlb,*.xlc,*.xba		setf xml
 au BufNewFile,BufRead psprint.conf,sofficerc		setf dosini
 
+" Libtool files
+au BufNewFile,BufRead *.lo,*.la,*.lai		setf sh
+
 " Lynx config files
 au BufNewFile,BufRead lynx.cfg			setf lynx
 

src/testdir/test_filetype.vim

@@ -673,7 +673,7 @@ def s:GetFilenameChecks(): dict<list<string>>
          '/tmp/bash-fc-3Ozjlw', '/tmp/bash-fc.3Ozjlw', 'PKGBUILD', 'APKBUILD', 'file.bash', '/usr/share/doc/bash-completion/filter.sh',
          '/etc/udev/cdsymlinks.conf', 'any/etc/udev/cdsymlinks.conf', 'file.bats', '.ash_history', 'any/etc/neofetch/config.conf', '.xprofile',
          'user-dirs.defaults', 'user-dirs.dirs', 'makepkg.conf', '.makepkg.conf', 'file.mdd', 'file.cygport', '.env', '.envrc', 'devscripts.conf',
-         '.devscripts'],
+         '.devscripts', 'file.lo', 'file.la', 'file.lai'],
     sieve: ['file.siv', 'file.sieve'],
     sil: ['file.sil'],
     simula: ['file.sim'],

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    796,
 /**/
     795,
 /**/