Translation stat fix (#5250)

* Add helper function for translation coverage

- Handle case where locale name does not match exactly

* remove debug statement

* Fixes

InvenTree/part/templatetags/i18n.py

@@ -10,9 +10,21 @@ from django.templatetags.i18n import TranslateNode
 
 import bleach
 
+import InvenTree.translation
+
 register = template.Library()
 
 
+@register.simple_tag()
+def translation_stats(lang_code):
+    """Return the translation percentage for the given language code"""
+
+    if lang_code is None:
+        return None
+
+    return InvenTree.translation.get_translation_percent(lang_code)
+
+
 class CustomTranslateNode(TranslateNode):
     """Custom translation node class, which sanitizes the translated strings for javascript use"""