Add highlighting for JSX fragment

[uniqueiniquity]

Adds support for #534 (also see facebook/jsx#93 for more info).

[sheetalkamat]

Instead of adding new rule for jsx-fragment,
Update: jsx-tag-without-attributes-in-expression and jsx-tag-without-attributes as:

  #jsx tags
  jsx-tag-without-attributes-in-expression:
    begin: |-
      (?x)
        (?<=[({\[,?=>:*]|&&|\|\||\?|\Wreturn|^return|\Wdefault|^)\s*
        (?=(<)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>))
    end: (?!\s*(<)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>))
    patterns:
    - include: '#jsx-tag-without-attributes'

  jsx-tag-without-attributes:
    name: meta.tag.without-attributes.tsx
    begin: (<)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>)
    end: (</)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>)

[uniqueiniquity]

Updated.

[sheetalkamat]

You also need to add the testcase mentioned in #534 here.

[sheetalkamat]

Need testcase + it would be just better to update jsx-tag-without attributes instead of creating new rule.

[uniqueiniquity]

Yeah the intent here was not for this to be a complete PR, I was actually just trying to get appveyor to run the tests since they're so broken locally.

[uniqueiniquity]

Now ready for review with test.