Add autofix to block-closing-brace-newline-before

[ota-meshi]

Which issue, if any, is this issue related to?

e.g. "Closes #000" or "None, as it's a documentation fix."

block-closing-brace-newline-before in #2829

Is there anything in the PR that needs further explanation?

e.g. "No, it's self explanatory."

ex.

• option: always***

  code:

  a { color: pink; }

  fixed:

  a { color: pink;
   }

• option: never***

  code:

  a {
  color: pink;
  }

  fixed:

  a {
  color: pink;}

[hudochenkov]

Good work!

[jeddy3]

@ota-meshi Thanks for starting this.

I've added a question about the three new tests.

[jeddy3]

Can you explain these tests, please?

I'd expected a { color: pink;;;\ntop: 0; ;;} and a { color: pink;;;\ntop: 0;; ;} to be accepted as neither has a newline before the closing brace.

a { color: pink;;;\ntop: 0; ; ; } does, but the spacing between the semicolons is transformed to a { color: pink;;;\ntop: 0;;;}.

I understand these are edge-cases, and if these artifacts are due to an unavoidable implementation detail then I'm happy to stick with them... I'd just like to understand them :)

[ota-meshi]

"never-multi-line" option does not allow whitespace before closing brace.
It can be understood also from the test case of "a { color: pink;\ntop: 0; }".

Also, when I tried, "a { color: pink;;;\ntop: 0; ;;}" and "a { color: pink;;;\ntop: 0;; ;}" is not allowed with this option.

If used the --fix option, no error is reported, so all errors need to be resolved,
"a { color: pink;;;\ntop: 0; ; ; }" is transformed to "a { color: pink;;;\ntop: 0;;;}".

[jeddy3]

• Added: block-closing-brace-newline-before autofix (#3442).