suggest a convention for python string quoting #19661

This convention is a useful way to distinguish strings that can be changed for clarity, for example, logging messages, and strings that can't be changed, for example, arguments to bitcoind or referencing dictionary keys. There are many current counterexamples of this convention in our functional tests, but it may be nice to have a convention going forward.

This README recommends adhering to the PEP-8 conventions, but that document says only "This PEP does not make a recommendation [on which kind of quote to use]."

I'm -0 on this.

However, if it is decided on, can we follow the Google Python Style Guide and add:

• It is okay to use the other quote character on a string to avoid the need to \\ escape within the string. (e.g. "Help! I'm scared of the linter!")
• Always use the three double-quote """ format for docstrings (per PEP 257)

-0 as well

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #19504 (Bump minimum python version to 3.6 by ajtowns)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

Too controversial for a simple style change. Closing for now.

Some questions from people about the -0 notations above. They are from the Apache voting system: https://www.apache.org/foundation/voting.html#expressing-votes-1-0-1-and-fractions

Agree the ~0 as well. While I think it's a clever idea, this is not a sufficiently common convention (that I know) so the energy we'll have to spend as reviewers and maintainers educating people about it is too much for the slight win in code comphrehension.