Added package names to 'Error loading MySQLdb module' error.

django/db/backends/mysql/base.py

@@ -25,7 +25,10 @@ try:
     import MySQLdb as Database
 except ImportError as e:
     from django.core.exceptions import ImproperlyConfigured
-    raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
+    raise ImproperlyConfigured(
+        'Error loading MySQLdb module: %s.\n'
+        'Did you install mysqlclient or MySQL-python?' % e
+    )
 
 from MySQLdb.constants import CLIENT, FIELD_TYPE                # isort:skip
 from MySQLdb.converters import Thing2Literal, conversions       # isort:skip