Fixed typos in chapter_21_mocking_2.asciidoc

Author: Cactusson

chapter_21_mocking_2.asciidoc

@@ -1214,7 +1214,7 @@ we want to check we are using the Django auth library:
 ====
 // CSANAD: I think the `diff` style snippets are better for renaming things.
 
-And we're down to 17 tests:
+And we're down to 18 tests:
 
 [subs="specialcharacters,quotes"]
 ----
@@ -1585,7 +1585,7 @@ Using mock.return_value::
   and thus check on how it gets used later in your code;
   this usually happens in the "assert" or "then" part of your test.
   Alternatively, you can _assign_ to it,
-  usally up-front in the "arrange" or "given" part of your test,
+  usually up-front in the "arrange" or "given" part of your test,
   as a way of saying
   "I want this mocked-out function to return a particular value".