Fix quoting of grep Regex in m_muttalias.

Required with grep >= 3.8, which complains about
 stray \ before "

In the NEWS file for grep 3.8:

  Regular expressions with stray backslashes now cause warnings, as
  their unspecified behavior can lead to unexpected results.

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Ignore case and non alphanumeric chars in SORT_OUTPUT=name.
 - Update dotlock code from mutt 2.2.1 (uses snprintf now).
 - Update rfc822 code from mutt 2.2.1.
+- Fix quoting of grep Regex in m_muttalias.
 
 ## [0.50] - 2022-02-25
 

m_muttalias.sh.in

@@ -3,7 +3,7 @@
 # -*-sh-*-
 #
 #     Copyright (C) 2000  Brian Salter-Duke <[email protected]>
-#                   2000-2018  Roland Rosenfeld <[email protected]>
+#                   2000-2022  Roland Rosenfeld <[email protected]>
 # 
 #     This program is free software; you can redistribute it and/or modify
 #     it under the terms of the GNU General Public License as published by
@@ -37,7 +37,7 @@ m_muttalias_query()
 	    # 2. alias nick [email protected] (Foo Bar)
 	    # 3. alias nick <[email protected]> (Foo Bar)
 	    grep -ia "$@" "$file" \
-	    | grep -a '^alias[ 	][ 	]*[^,][^,]*[ 	][ 	]*\([^,]\|\\\".*\\\"\)*$' \
+	    | grep -a '^alias[ 	][ 	]*[^,][^,]*[ 	][ 	]*\([^,]\|".*"\)*$' \
 	    | sed -E -e 's/^alias[[:blank:]]+([^[:blank:]]+)[[:blank:]]+("[^"]+"|[^<>()]+)[[:blank:]]+<([^<>()]+)>.*$/\3	\2	alias \1/' \
 		     -e 's/^alias[[:blank:]]+([^[:blank:]]+)[[:blank:]]+([^<>()]+)[[:blank:]]+\(([^()<>]+)\).*$/\2	\3	alias \1/' \
 		     -e 's/^alias[[:blank:]]+([^[:blank:]]+)[[:blank:]]+<([^<>()]+)>[[:blank:]]+\(([^()<>]+)\).*$/\2	\3	alias \1/' \