fix: allow blank lines and comments in cases that do not stop execution

[koh28]

Fixes #1196

This PR allows:

switch (number) {
  case 1:
    // comment
  case 2:
    doSomething();
}

switch (number) {
  case 1:
    
  case 2:
    doSomething();
}

but does not allow:

switch (number) {
  case 1:
    // comment
    doSomething();
  case 2:
    doSomething();
}

[CLAassistant]

All committers have signed the CLA.

[bartlomieju]

Hey @koh28, thanks for the PR. Can you please sign the CLA so we can land this PR?

[koh28]

I signed it