[1.7.x] Fixed spelling errors in documentation.

Backport of b5ce21accb from master

docs/ref/django-admin.txt

@@ -1121,7 +1121,7 @@ please read :ref:`migration-squashing`.
 By default, Django will try to optimize the operations in your migrations
 to reduce the size of the resulting file. Pass ``--no-optimize`` if this
 process is failing for you or creating incorrect migrations, though please
-also file a Django bug report about the behaviour, as optimization is meant
+also file a Django bug report about the behavior, as optimization is meant
 to be safe.
 
 

docs/spelling_wordlist

@@ -555,6 +555,7 @@ sqlflush
 sqlindexes
 sqlmigrate
 sqlsequencereset
+squashmigrations
 ssi
 stacktrace
 startswith
@@ -661,6 +662,7 @@ unrendered
 Unreviewed
 unsanitized
 unsets
+unsquashed
 untar
 url
 urlencode

docs/topics/migrations.txt

@@ -398,7 +398,7 @@ Squashing migrations
 --------------------
 
 You are encouraged to make migrations freely and not worry about how many you
-have; the migration code is optimised to deal with hundreds at a time without
+have; the migration code is optimized to deal with hundreds at a time without
 much slowdown. However, eventually you will want to move back from having
 several hundred migrations to just a few, and that's where squashing comes in.
 

docs/topics/testing/tools.txt

@@ -1196,7 +1196,7 @@ have been overridden, like this::
 .. versionchanged:: 1.7
 
     Previously, you could only simulate the deletion of a setting which was
-    explicitely overridden.
+    explicitly overridden.
 
 When overriding settings, make sure to handle the cases in which your app's
 code uses a cache or similar feature that retains state even if the setting is