Add translations for min and max tag errors.

public/language/en_GB/error.json

@@ -58,6 +58,9 @@
 	"too-many-posts-newbie": "As a new user, you can only post once every %1 second(s) until you have earned %2 reputation - please wait before posting again",
 	"tag-too-short": "Please enter a longer tag. Tags should contain at least %1 character(s)",
 	"tag-too-long": "Please enter a shorter tag. Tags can't be longer than %1 character(s)",
+	"not-enough-tags": "Not enough tags. Topics must have at least %1 tag(s)",
+        "too-many-tags": "Too many tags. Topics can't have more than %1 tag(s)",
+
 	"file-too-big": "Maximum allowed file size is %1 kB - please upload a smaller file",
 
 	"cant-vote-self-post": "You cannot vote for your own post",