Add "documentation" to the checker tool

Author: neilmcgovern

tools/checker

@@ -1,5 +1,8 @@
 #!/usr/bin/env bash
 # Very simple tool to help manage floods of PRs
+# Needs GitHub CLI installed: https://cli.github.com/manual/
+# As this is so simple, I don't consider it copyrightable
+
 for I in `gh pr list|cut -f 1`; do
     gh pr diff $I
     read -p"Accept $I? " foo