Parsing for Q# Attributes

[jviszlai]

Adds support for parsing the syntax of attributes. Includes some specific error handling for if the ending tag is missing on an attribute or the arguments are missing for an attribute, as well as context verification so that the attribute is only above an operation, function, or type definition.

Making this a draft pull request until a feature branch exists for attributes.

Targets #81

[bettinaheim]

@jviszlai Thanks again for the contribution, and sorry for the delay in processing!
I don't know what the best way is to contact you, but if you reach out and contact me on my Microsoft address we've got a surprise for you. :) Purely optional of course.

[jviszlai]

@jviszlai Thanks again for the contribution, and sorry for the delay in processing!
I don't know what the best way is to contact you, but if you reach out and contact me on my Microsoft address we've got a surprise for you. :) Purely optional of course.

@bettinaheim No worries! I don't have access to anything in Microsoft since my internship ended so I couldn't find your email. Thanks again for the opportunity to learn about this!

[bettinaheim]

@jviszlai
Thank for this awesome PR! I suggest to merge this into a separate branch so I can update it with the changes from master, and can add the necessary support to actually do something cool with the attributes. :) Sounds good?

Let me know if you would like to pick up some work, and whether you would like to continue on this, or maybe you would also like to look at something else. Cheers!

[jviszlai]

@bettinaheim Sounds good! I'll mark it as ready to be merged into the hackathon branch if that works?

[bettinaheim]

@jviszlai Perfect, thanks!

[bettinaheim]

Thank you for this awesome contribution!