scripts/kernel-doc: Escape all literal braces in regexes

Commit 701b3a3c0ac4 ("PATCH scripts/kernel-doc") fixed the two
instances of literal braces that Perl 5.28 warns about, but there are
still more than it doesn't warn about.

Escape all left braces that are treated as literal characters.  Also
escape literal right braces, for consistency and to avoid confusing
bracket-matching in text editors.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 31a34ce..8f0f508 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -1062,7 +1062,7 @@
     my $x = shift;
     my $file = shift;
 
-    if ($x =~ /(struct|union)\s+(\w+)\s*{(.*)}/) {
+    if ($x =~ /(struct|union)\s+(\w+)\s*\{(.*)\}/) {
 	my $decl_type = $1;
 	$declaration_name = $2;
 	my $members = $3;
@@ -1148,20 +1148,20 @@
 				}
 			}
 		}
-		$members =~ s/(struct|union)([^\{\};]+)\{([^\{\}]*)}([^\{\}\;]*)\;/$newmember/;
+		$members =~ s/(struct|union)([^\{\};]+)\{([^\{\}]*)\}([^\{\}\;]*)\;/$newmember/;
 	}
 
 	# Ignore other nested elements, like enums
-	$members =~ s/(\{[^\{\}]*})//g;
+	$members =~ s/(\{[^\{\}]*\})//g;
 
 	create_parameterlist($members, ';', $file, $declaration_name);
 	check_sections($file, $declaration_name, $decl_type, $sectcheck, $struct_actual);
 
 	# Adjust declaration for better display
-	$declaration =~ s/([{;])/$1\n/g;
-	$declaration =~ s/}\s+;/};/g;
+	$declaration =~ s/([\{;])/$1\n/g;
+	$declaration =~ s/\}\s+;/};/g;
 	# Better handle inlined enums
-	do {} while ($declaration =~ s/(enum\s+{[^}]+),([^\n])/$1,\n$2/);
+	do {} while ($declaration =~ s/(enum\s+\{[^\}]+),([^\n])/$1,\n$2/);
 
 	my @def_args = split /\n/, $declaration;
 	my $level = 1;
@@ -1171,12 +1171,12 @@
 		$clause =~ s/\s+$//;
 		$clause =~ s/\s+/ /;
 		next if (!$clause);
-		$level-- if ($clause =~ m/(})/ && $level > 1);
+		$level-- if ($clause =~ m/(\})/ && $level > 1);
 		if (!($clause =~ m/^\s*#/)) {
 			$declaration .= "\t" x $level;
 		}
 		$declaration .= "\t" . $clause . "\n";
-		$level++ if ($clause =~ m/(\{)/ && !($clause =~m/}/));
+		$level++ if ($clause =~ m/(\{)/ && !($clause =~m/\}/));
 	}
 	output_declaration($declaration_name,
 			   'struct',
@@ -1244,7 +1244,7 @@
     # strip #define macros inside enums
     $x =~ s@#\s*((define|ifdef)\s+|endif)[^;]*;@@gos;
 
-    if ($x =~ /enum\s+(\w+)\s*{(.*)}/) {
+    if ($x =~ /enum\s+(\w+)\s*\{(.*)\}/) {
 	$declaration_name = $1;
 	my $members = $2;
 	my %_members;
@@ -1785,7 +1785,7 @@
     }
 
     while (1) {
-	if ( $x =~ /([^{};]*)([{};])(.*)/ ) {
+	if ( $x =~ /([^\{\};]*)([\{\};])(.*)/ ) {
             if( length $prototype ) {
                 $prototype .= " "
             }