In both the:

- Unquoted case, where extra whitespace is at the edges of what can
  be parsed as the value.

- Quoted case, where extra whitespace is next to but outside of the
  quotes.

The case where the whitespace is at the edges of the quoted value
and *inside* the quotes, and thus part of the value, is already
covered in gitpython-developers#2036. (That is merely renamed here, to distinguish it.)