Post-black string format conversion

[sadielbartholomew]

Close #46, at least for the vast majority of cases, particularly those involving much longer lines, with mixed and/or non f-string formatted strings

Note there are lots of new-line characters peppered about the strings especially for user messages, which I will remove (they are not useful since users will be viewing these on terminals or IDEs or similar of variable width where standard line wrapping will apply for readability, and these custom new lines could cause weird gaps and wrapping issues) but I will do that as a separate issue since it is distinct and a significant task in its own right. I have generally only removed/added new line characters to preserve the behaviour of the string with any change of formatting.

I will do a self-review before merging since there is so little testing at present (one of the next priorities it to get some and increase coverage!) so I won't be convinced I haven't inadvertently broken something during the conversion until I've checked the pushed line changes carefully.

[sadielbartholomew]

One commit added with some fixes noticed in self-review. I am satisfied this is all good after that, so merging.