Merge pull request #237 from david-mitchell/patch-1

Fix grammar.

CppCoreGuidelines.md

@@ -4290,8 +4290,8 @@ Make sure that every member of the derived class is initialized.
 
 ## <a name="SS-copy"></a> C.copy: Copy and move
 
-Value type should generally be copyable, but interfaces in a class hierarchy should not.
-Resource handles, may or may not be copyable.
+Value types should generally be copyable, but interfaces in a class hierarchy should not.
+Resource handles may or may not be copyable.
 Types can be defined to move for logical as well as performance reasons.
 
 ### <a name="Rc-copy-assignment"></a> C.60: Make copy assignment non-`virtual`, take the parameter by `const&`, and return by non-`const&`