scripts: drop redundant double-quotes: "$var" -> $var (Perl)

Closes #21009

scripts/cd2cd

@@ -89,7 +89,7 @@ sub single {
     my $salist = 0;
     my $copyright;
     my $spdx;
-    open(F, "<:crlf", "$f") ||
+    open(F, "<:crlf", $f) ||
         return 1;
     while(<F>) {
         $line++;

scripts/cd2nroff

@@ -216,7 +216,7 @@ sub single {
     my $title;
 
     if(defined($f)) {
-        if(!open($fh, "<:crlf", "$f")) {
+        if(!open($fh, "<:crlf", $f)) {
             print STDERR "cd2nroff failed to open '$f' for reading: $!\n";
             return 1;
         }

scripts/cdall

@@ -35,7 +35,7 @@ sub convert {
     closedir $dh;
 
     for my $cd (@cd) {
-        my $nroff = "$cd";
+        my $nroff = $cd;
         $nroff =~ s/\.md\z/.3/;
         print "$dir/$cd = $dir/$nroff\n";
         system('./scripts/cd2nroff', ('-d', $dir, "$dir/$cd"));

scripts/checksrc.pl

@@ -412,7 +412,7 @@ readskiplist();
 readlocalfile($file);
 
 do {
-    if("$wlist" !~ / $file /) {
+    if($wlist !~ / $file /) {
         my $fullname = $file;
         $fullname = "$dir/$file" if($fullname !~ '^\.?\.?/');
         scanfile($fullname);

scripts/delta

@@ -67,7 +67,7 @@ my $contribs = $acontribs - $bcontribs;
 # number of setops:
 sub setopts {
     my ($f)=@_;
-    open(H, "$f");
+    open(H, $f);
     my $opts;
     while(<H>) {
         if(/^  CURLOPT(|DEPRECATED)\(/ && ($_ !~ /OBSOLETE/)) {

scripts/mdlinkcheck

@@ -154,7 +154,7 @@ sub storelink {
 sub findlinks {
     my ($f) = @_;
     my $line = 1;
-    open(F, "<:crlf", "$f") ||
+    open(F, "<:crlf", $f) ||
         return;
 
     # is it a markdown extension?

scripts/mk-ca-bundle.pl

@@ -166,7 +166,7 @@ sub HELP_MESSAGE() {
     print "\t-b\tbackup an existing version of ca-bundle.crt\n";
     print "\t-d\tspecify Mozilla tree to pull certdata.txt or custom URL\n";
     print "\t\t  Valid names are:\n";
-    print "\t\t    ", join(", ", map { ($_ =~ m/$opt_d/) ? "$_ (default)" : "$_" } sort keys %urls), "\n";
+    print "\t\t    ", join(", ", map { ($_ =~ m/$opt_d/) ? "$_ (default)" : $_ } sort keys %urls), "\n";
     print "\t-f\tforce rebuild even if certdata.txt is current\n";
     print "\t-i\tprint version info about used modules\n";
     print "\t-k\tallow URLs other than HTTPS, enable HTTP fallback (insecure)\n";
@@ -478,7 +478,7 @@ my @precert;
 my $cka_value;
 my $valid = 0;
 
-open(TXT,"$txt") or die "Could not open $txt: $!\n";
+open(TXT, $txt) or die "Could not open $txt: $!\n";
 while(<TXT>) {
     if(/\*\*\*\*\* BEGIN LICENSE BLOCK \*\*\*\*\*/) {
         print CRT;

scripts/nroff2cd

@@ -43,7 +43,7 @@ my $nroff2cd = "0.1"; # to keep check
 
 sub single {
     my ($f)=@_;
-    open(F, "<:crlf", "$f") ||
+    open(F, "<:crlf", $f) ||
         return 1;
     my $line;
     my $title;
@@ -67,7 +67,7 @@ sub single {
                 # remove leading directory
                 $f =~ s/(.*?\/)//;
                 close(F);
-                open(F, "<:crlf", "$f") || return 1;
+                open(F, "<:crlf", $f) || return 1;
             }
             if($d =~ /^\.TH ([^ ]*) (\d) \"(.*?)\" ([^ \n]*)/) {
                 # header, this needs to be the first thing after leading comments