Use flake8-implicit-str-concat

[MetRonnie]

https://github.com/flake8-implicit-str-concat/flake8-implicit-str-concat

Use these 2 rules (better documented by ruff!):

• https://docs.astral.sh/ruff/rules/single-line-implicit-string-concatenation/
  • Prevents:

    z = "The quick " "brown fox."`
    

    (I spotted an example of this somewhere a while ago, can't remember where though)
• https://docs.astral.sh/ruff/rules/multi-line-implicit-string-concatenation/
  • Prevents:

    z = "The quick brown fox jumps over the lazy "\
        "dog."
    

Check List

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Dev dependency changes don't apply to conda-environment.yml
• No tests, changelog etc needed as not user-facing
• If this is a bug fix, PR should be raised against the relevant ?.?.x branch.