[clangd] Improve BlockEnd inlay hints presentation

[daiyousei-qz]

Including:

1. Explicitly state a function call. "// if foo" -> "// if foo()" or "// if foo(...)"
2. Print literal nullptr
3. Escape for abbreviated string
4. Adjust min line limit to 10

Fixes issue clangd/clangd#1807

[daiyousei-qz]

@HighCommander4 @sam-mccall for opinions.

I haven't update the test because the hard-coded limit 10 makes it hard to write the tests. Any opinion of how to structure this?

[HighCommander4]

Thanks, the behaviour changes look reasonable to me.

I haven't update the test because the hard-coded limit 10 makes it hard to write the tests. Any opinion of how to structure this?

I would suggest running most tests with HintMinLineLimit = 2 (and then have one test for the behaviour with HintMinLineLimit = 10).

To allow the tests to change HintMinLineLimit, we could give the inlayHints() function an optional parameter to specify it (could wrap it in an InlayHintOptions class for adding other options in the future).

[HighCommander4]

(see previous comment)

[HighCommander4]

Superseded by #136106.