Redo of PR#5345. Fixed spelling and typographical errors found by CodeSpell.

Signed-off-by: Shaun Case <warmsocks@gmail.com>
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/scripts/check_names.py b/tests/scripts/check_names.py
index 8bb4923..96117a2 100755
--- a/tests/scripts/check_names.py
+++ b/tests/scripts/check_names.py
@@ -813,7 +813,7 @@
 
     def check_for_typos(self):
         """
-        Perform a check that all words in the soure code beginning with MBED are
+        Perform a check that all words in the source code beginning with MBED are
         either defined as macros, or as enum constants.
         Assumes parse_names_in_source() was called before this.