Fixed some typos in comments, docstrings, and tests.

django/core/files/utils.py

@@ -26,7 +26,7 @@ def validate_file_name(name, allow_relative_path=False):
 
 class FileProxyMixin:
     """
-    A mixin class used to forward file methods to an underlaying file
+    A mixin class used to forward file methods to an underlying file
     object.  The internal file object has to be called "file"::
 
         class FileProxy(FileProxyMixin):

django/db/models/sql/query.py

@@ -699,7 +699,7 @@ class Query(BaseExpression):
         # All concrete fields that are not part of the defer mask must be
         # loaded. If a relational field is encountered it gets added to the
         # mask for it be considered if `select_related` and the cycle continues
-        # by recursively caling this function.
+        # by recursively calling this function.
         for field in opts.concrete_fields:
             field_mask = mask.pop(field.name, None)
             if field_mask is None: