Webconfig: Fix initial tab

For some reason the url is now

http://localhost:$PORT/$RANDOM/#!/$TAB

while this created

http://localhost:$PORT/$RANDOM/#$TAB

which redirected to

http://localhost:$PORT/$RANDOM/#!/colors#$TAB

i.e. the "colors" tab with a useless unmatched anchor.

share/tools/web_config/webconfig.py

@@ -1527,7 +1527,7 @@ if len(sys.argv) > 1:
         "abbreviations",
     ]:
         if tab.startswith(sys.argv[1]):
-            initial_tab = "#" + tab
+            initial_tab = "#!/" + tab
             break
 
 url = "http://localhost:%d/%s/%s" % (PORT, authkey, initial_tab)