Update: The format sentence end strings, making their usage more clear.

Update: The format sentence end strings, making their usage more clear.

The sentence ends, unlike the other similar global static strings, does not have the "_single" in the name.
Add the "_single" in the name and then for consistency addthe case where there should be no "_single".

These cases are as a result now handled:
- ".%r".
- "'.%r".
- "%[.%]%r"
- "%['.%]%r"
- "%[%[.%]%]%r"
- "%[%['.%]%]%r"