patch 9.1.0544: filetype: ldapconf files are not recognized

Problem:  filetype: ldapconf files are not recognized
Solution: Detect '.ldaprc', 'ldap.conf' and 'ldaprc' files as ldapconf
          filetype, include a simple ldapconf ftplugin file
          (Riley Bruins)

[Specification](https://www.openldap.org/software//man.cgi?query=ldap.conf&sektion=5&apropos=0&manpath=OpenLDAP+2.4-Release)

closes: #15176

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/filetype.vim

@@ -1250,6 +1250,9 @@ au BufNewFile,BufRead */etc/limits,*/etc/*limits.conf,*/etc/*limits.d/*.conf	set
 " LambdaProlog or SML (see dist#ft#FTmod for *.mod)
 au BufNewFile,BufRead *.sig			call dist#ft#FTsig()
 
+" LDAP configuration
+au BufNewFile,BufRead ldaprc,.ldaprc,ldap.conf	setf ldapconf
+
 " LDAP LDIF
 au BufNewFile,BufRead *.ldif			setf ldif
 

runtime/ftplugin/ldapconf.vim

@@ -0,0 +1,13 @@
+" Vim filetype plugin
+" Language:	ldap.conf(5) configuration file.
+" Maintainer:	Riley Bruins <ribru17@gmail.com>
+" Last Change:	2024 Jul 06
+
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
+setl comments=:# commentstring=#\ %s
+
+let b:undo_ftplugin = 'setl com< cms<'