Remove existing space when auto-inserting space

[vkbo]

Summary:

This PR adds a simple look-back check to see if the character before the one that triggered the insertion of a non-breaking space was also a space character. If so, that character is removed before the new space is inserted.

Related Issue(s):

Resolves #1061

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• All flake8 checks are passing and the style guide is followed
• Documentation (as docstrings) is complete and understandable
• Only files that have been actively changed are committed