BaseTools: Fix various typos

Fix various typos in BaseTools.

Signed-off-by: Cœur <coeur@gmx.fr>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/Common/ToolDefClassObject.py

@@ -105,7 +105,7 @@ class ToolDefClassObject(object):
 
     ## IncludeToolDefFile
     #
-    # Load target.txt file and parse it as if it's contents were inside the main file
+    # Load target.txt file and parse it as if its contents were inside the main file
     #
     # @param Filename:  Input value for full path of tools_def.txt
     #