proselint: trim the markdowns before running proselint

Since the quoted parts generate too many false positives

.github/scripts/cleanmd.pl

@@ -0,0 +1,25 @@
+#!/usr/bin/env perl
+# Copyright (C) Daniel Stenberg, <[email protected]>, et al.
+#
+# SPDX-License-Identifier: curl
+#
+# Input: a markdown file, it gets modified *in place*
+#
+# The main purpose is to strip off quotes, lines starting with four spaces,
+# so that the result can be run through proselint better.
+#
+
+my $f = $ARGV[0];
+
+open(F, "<$f") or die;
+
+while(<F>) {
+    $_ =~ s/^    .*//g;
+
+    push @out, $_;
+}
+close(F);
+
+open(O, ">$f") or die;
+print O @out;
+close(O);

.github/workflows/proselint.yml

@@ -22,6 +22,9 @@ jobs:
     - name: install prereqs
       run: sudo apt-get install python3-proselint
 
+    - name: trim off quoted parts
+      run: find docs -name "*.md" -print0 | xargs -0 -n1 .github/scripts/cleanmd.pl
+
     # config file help: https://github.com/amperser/proselint/
     - name: store proselint config
       run: |