Refactor format_args! expansion parsing

[camsteffen]

Introduces FormatExpn::parse and FormatArgsExpn::parse. Motivated by rust-lang/rust#83302, so I only have to change Clippy in one place. Fixed an FP along the way.

I also allowed needless_bool in macros because I often want to do if_chain! { .. then { true } else { false } }.

changelog: Fix false positive in useless_format when some text is appended or prepended to a single string with some useless formatting params
changelog: Allow needless_bool in macros

[flip1995]

r? @xFrednet Can you take over this review please? (rust-highfive was down, so I'll give the 2 unassigned PRs to you)

[xFrednet]

Sure, I'm happy to take them over! 🙃

[xFrednet]

^^ thank you! I believe that @flip1995 would also like to stay assigned to double-check my review later. 🙃

[xFrednet]

Hey, awesome work, it took some time digging though it all but the result is worth it. Thank you for the nice refactoring!

clippy_lints/src/explicit_write.rs still contains some lint messages with punctuation and a suggestion in the main message (lines 111ff). Could you update the lint emission to display the help message using span_lint_and_help while you're in the area?

[camsteffen]

Thanks for the thorough review @xFrednet. I addressed your comments.

[xFrednet]

Awesome, this looks good to me 👍

Hey @flip1995, I'm done with my review and would hand this over to you now. If you weren't taking over, I would ask @camsteffen to squash his fixup commits before merging it. 🙃

[flip1995]

@xFrednet Thanks for doing the review!

@camsteffen please squash the fixup commits and then r=xFrednet 👍

[camsteffen]

@bors r=xFrednet

[bors]

📌 Commit 306f9e8 has been approved by xFrednet

[bors]

⌛ Testing commit 306f9e8 with merge bf4512e...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: xFrednet
Pushing bf4512e to master...