Support parsing missing keywords as ids

[jackkoenig]

Reset, AsyncReset, Interval, attach, assert, assume, and cover have all
been added as keywords but not added to the allowlist for parsing as
ids.

Contributor Checklist

• [NA] Did you add Scaladoc to every public function/method?
• [NA] Did you update the FIRRTL spec to include every new feature/behavior?
• Did you add at least one test demonstrating the PR?
• Did you delete any extraneous printlns/debugging code?
• Did you specify the type of improvement?
• Did you state the API impact?
• Did you specify the code generation impact?
• Did you request a desired merge strategy?
• Did you add text to be included in the Release Notes for this change?

Type of Improvement

• bug fix

API Impact

Accept more keywords as ids in parsing

Backend Code Generation Impact

No impact

Desired Merge Strategy

• Squash

Release Notes

Support parsing more keywords as identifiers: Reset, AsyncReset, Interval, attach, assert, assume, and cover

Reviewer Checklist (only modified by reviewer)

• Did you add the appropriate labels?
• Did you mark the proper milestone (1.2.x, 1.3.0, 1.4.0) ?
• Did you review?
• Did you check whether all relevant Contributor checkboxes have been checked?
• Did you mark as Please Merge?