gtkdocize: don't backslash escape regular characters in grep
Grep 3.8 warns about wrongly escaped characters:
$ echo | grep '\,'
grep: warning: stray \ before ,
$ echo | grep '\ '
grep: warning: stray \ before white space
$ echo | grep ' \-'
grep: warning: stray \ before -
Note that a '\-' as first character is OK, to not interpret the pattern as command line argument:
$ echo | grep '\--Wall'
Edited by Thomas Haller