also work for color maps with underscores in their name

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@56808 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.colors/Makefile

@@ -14,7 +14,7 @@ default: cmd
 # Insert thumbnail previews
 v.colors.tmp.html: $(BIN)/v.colors$(EXE) thumbnails
 	$(call htmldesc,$<,$@)
-	sed 's!^<dd><b>\([a-z0-9.]*\)</b>:!<dd><img width="80" height="12" src="Colortable_\1.png"> <b>\1</b>:!' "$@" > "$@.tmp"
+	sed 's!^<dd><b>\([a-z0-9._]*\)</b>:!<dd><img width="80" height="12" src="Colortable_\1.png"> <b>\1</b>:!' "$@" > "$@.tmp"
 	mv -f "$@.tmp" "$@"
 	$(MAKE) thumbnails