modulecmd: add 'find' as alias of sub-cmd 'search'

In the Tcl Environment Module version 4 and newer the sub-cmds
'appropos' and 'keyword' have been replaced by the sub-cmd 'search'.
Thsi conflicts with Pmodules 'search' sub-cmd. In the future we might
have to rename the 'search' sub-cmd to 'find'.

Pmodules/modulecmd.bash.in

@@ -2859,6 +2859,9 @@ case ${subcommand} in
 	rm )
 		subcommand='unload'
 		;;
+	find )
+		subcommand='search'
+		;;
 	switch )
 		subcommand='swap'
 		;;