speed up make quick_www

We add `-Q` to `bin/gen-other-html.sh` to add a mode
that will only update an entry non-index.html if it
is missing or out of date.

Added `make quick_other_html` that calls `bin/gen-other-html.sh`
with the `-Q` quick mode option.

Changed `bin/gen-other-html.sh` VERSION from "1.2.6 2024-08-05"
to "1.3 2024-08-11".

bin/quick-readme2index.sh

@@ -521,7 +521,7 @@ fi
 
 # determine if we need to run the tool
 #
-# Check if the non-empty index.html is newer than the .entry.json file.
+# Check if the non-empty index.html is newer than both README.md and .entry.json files.
 #
 if [[ $V_FLAG -ge 5 ]]; then
     echo "$0: debug[5]: listing of important files, if they exist, starts below" 1>&2