Add commas to improve readability in GDNative C++ example (#4513)

Co-authored-by: Hugo Locurcio <[email protected]>

tutorials/scripting/gdnative/gdnative_cpp_example.rst

@@ -42,8 +42,8 @@ You can download these repositories from GitHub or let Git do the work for you.
 Note that these repositories now have different branches for different versions
 of Godot. GDNative modules written for an earlier version of Godot will work in
 newer versions (with the exception of one breaking change in ARVR interfaces
-between 3.0 and 3.1) but not vice versa so make sure you download the correct
-branch. Also note that the version of Godot you use to generate the ``api.json``
+between 3.0 and 3.1) but not vice versa, so make sure you download the correct
+branch. Also, note that the version of Godot you use to generate the ``api.json``
 with becomes your minimum version.
 
 If you are versioning your project using Git, it is a good idea to add them as