Variable highlighting in for-each loop

[sadikovi]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

I found when working on other issue that variables in for-each loops are not scoped correctly, for example:

class Test {
  void func() {
    // correctly highlighted in for loop
    for (int i = 0; i < 10; i++) {
      // do something
    }

    // incorrectly highlighted and scoped in for-each loop
    for (int i : elements) {
      // do something
    }

    // incorrectly highlighted and scoped in for-each loop
    for (HashMap<String, String> map : elementsFunc()) {
      // do something
    }
  }
}

Before patch:

After patch:

I simply extended the list of characters that terminate variable patterns and added : as such. Added test to cover this scenario.

Alternate Designs

None were considered.

Benefits

Fixes variable highlighting in for-each loops.

Possible Drawbacks

Should not be any.

Applicable Issues

None

[sadikovi]

@50Wliu could you review this PR? Thanks!

I found this inconsistency when working on Java 10 var support, so I thought I might as well fix it (more or less).

[sadikovi]

ping @50Wliu