improved the h2 title for HTML from markdown other than README.md

For HTML files from markdown files other than README.md, the h2
title now refers to the HTML file instead of the markdown file.

Changed `bin/gen-other-html.sh` VERSION from "1.2.3 2024-04-28"
to "1.2.4 2024-05-31" to perform the above.

Perform `make www` to perform the above and test under macOS.

bin/gen-other-html.sh

@@ -84,7 +84,7 @@ shopt -s globstar	# enable ** to match all files and zero or more directories an
 
 # set variables referenced in the usage message
 #
-export VERSION="1.2.3 2024-04-28"
+export VERSION="1.2.4 2024-05-31"
 NAME=$(basename "$0")
 export NAME
 export V_FLAG=0
@@ -163,6 +163,7 @@ Exit codes:
 
 $NAME version: $VERSION"
 
+
 # parse command line
 #
 while getopts :hv:Vd:D:nNt:T:p:u:w: flag; do
@@ -579,6 +580,8 @@ for YYYY in $(< "$TOP_FILE"); do
 	    # determine the HTML file
 	    #
 	    export HTML_FILE=${MD_FILE//\.md/.html}
+	    HTML_BASENAME=$(basename "$HTML_FILE")
+	    export HTML_BASENAME
 
 	    # determine the description arg
 	    #
@@ -591,7 +594,7 @@ for YYYY in $(< "$TOP_FILE"); do
 
 	    # determine the HEADER_2 arg
 	    #
-	    export HEADER_2="HEADER_2=$MD_BASENAME for $YYYY_DIR"
+	    export HEADER_2="HEADER_2=$HTML_BASENAME for $YYYY_DIR"
 
 	    # determine the number of levels in path of MD_FILE from topdir
 	    #