managen: warn on excessively long help texts

Help texts at 49 characters or longer get a warning displayed because
they make --help output uglier and we should make an effort to keep the
help texts short and succinct.

The warning is only for display, it does not break the build. That is
left for the future if necessary.

I picked 49 because the longest current text is 48.

Closes #13895

scripts/managen

@@ -783,7 +783,9 @@ sub getshortlong {
     my $protocols;
     my $category;
     my $start = 0;
+    my $line = 0;
     while(<F>) {
+        $line++;
         if(!$start) {
             if(/^---/) {
                 $start = 1;
@@ -798,6 +800,11 @@ sub getshortlong {
         }
         elsif(/^Help: (.*)/i) {
             $help=$1;
+            my $len = length($help);
+            if($len >= 49) {
+                printf STDERR "$f:$line:1:WARN: oversized help text: %d characters\n",
+                    $len;
+            }
         }
         elsif(/^Arg: (.*)/i) {
             $arg=$1;