Fix: Status bar text template key name

This commit fixes the name of the `status_bar_text` setting in the
Preferences.sublime-settings-hints. The wrong name caused PackageDev
to not recognize the `git_gutter_status_bar_text` setting in the user
preferences as valid key.

Author: DeathAxe

Preferences.sublime-settings-hints

@@ -230,7 +230,7 @@
     //   {{line_committer_tz}   -- the timezone string of commit
     //   {{line_summary}}       -- the first line of the commit message
     //   {{line_previous}}      -- the hash of the previous commit
-    "status_bar_text": [
+    "git_gitter_status_bar_text": [
         "{% if repo and branch %}",
             "{% if not st_git_status %}",
                 "{{repo}}/{{branch}}",