Merge pull request #14260 from edx/jibsheet/export-docs

It's always bugged me that the help strings were nonsensical

cms/djangoapps/contentstore/management/commands/export.py

@@ -14,16 +14,19 @@ from opaque_keys.edx.locations import SlashSeparatedCourseKey
 
 class Command(BaseCommand):
     """
-    Export the specified data directory into the default ModuleStore
+    Export the specified course into a directory.  Output will need to be tar zxcf'ed.
     """
-    help = 'Export the specified data directory into the default ModuleStore'
+    help = 'Export the specified course into a directory'
 
     def add_arguments(self, parser):
         parser.add_argument('course_id')
         parser.add_argument('output_path')
 
     def handle(self, *args, **options):
-        """Execute the command"""
+        """
+        Given a course id(old or new style), and an output_path folder.  Export the
+        corresponding course from mongo and put it directly in the folder.
+        """
         try:
             course_key = CourseKey.from_string(options['course_id'])
         except InvalidKeyError: