Change hint format for main filtered search dropdown

Change hint format from `type<value>` to `type:value` so it matches
the required syntax to perform filtering

Fixes #29786

app/assets/javascripts/filtered_search/dropdown_hint.js

@@ -61,7 +61,7 @@ class DropdownHint extends gl.FilteredSearchDropdown {
       .map(tokenKey => ({
         icon: `fa-${tokenKey.icon}`,
         hint: tokenKey.key,
-        tag: `<${tokenKey.tag}>`,
+        tag: `:${tokenKey.tag}`,
         type: tokenKey.type,
       }));