Support highlighting of ripgrep output (bug#44983)

* etc/grep.txt: Add ripgrep samples.

* lisp/progmodes/grep.el (grep-match-regexp): Highlight ripgrep matches too.
(grep-regexp-alist): Remove $ to highlight ripgrep binary file matches.

etc/grep.txt

@@ -85,6 +85,12 @@ git --no-pager grep -inH -p -e "org-element-map"
 lisp/org/org.el=20969=(defun org-fill-paragraph (&optional justify)
 lisp/org/org.el:21047:		      (org-element-map
 
+* ripgrep
+
+rg -nH --color always --no-heading -e grep-match-regexp
+lisp/progmodes/grep.el:608:        (while (re-search-forward grep-match-regexp end 1)
+Binary file emacs.info matches (found "\u{0}" byte around offset 2222525)
+
 * unknown greps
 
 grep -nH -e "xyzxyz" ../info/*

lisp/progmodes/grep.el

@@ -100,7 +100,7 @@ To change the default value, use \\[customize] or call the function
   :set #'grep-apply-setting
   :version "22.1")
 
-(defcustom grep-match-regexp "\033\\[0?1;31m\\(.*?\\)\033\\[[0-9]*m"
+(defcustom grep-match-regexp "\033\\[\\(?:0?1;\\)?31m\\(.*?\\)\033\\[[0-9]*m"
   "Regular expression matching grep markers to highlight.
 It matches SGR ANSI escape sequences which are emitted by grep to
 color its output.  This variable is used in `grep-filter'."
@@ -412,7 +412,7 @@ Notice that using \\[next-error] or \\[compile-goto-error] modifies
                (- mend beg))))))
      nil nil
      (3 '(face nil display ":")))
-    ("^Binary file \\(.+\\) matches$" 1 nil nil 0 1))
+    ("^Binary file \\(.+\\) matches" 1 nil nil 0 1))
   "Regexp used to match grep hits.
 See `compilation-error-regexp-alist' for format details.")
 

test/README

@@ -113,7 +113,8 @@ $EMACS_HYDRA_CI indicates the hydra environment, and $EMACS_EMBA_CI
 indicates the emba environment, respectively.
 
 
-(Also, see etc/compilation.txt for compilation mode font lock tests.)
+(Also, see etc/compilation.txt for compilation mode font lock tests
+and etc/grep.txt for grep mode font lock tests.)
 
 
 This file is part of GNU Emacs.