Add proper boundary-checking for and=, or=

[winstliu]

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

and= and or= were being lumped with the other compound assignment operators, which since they're symbols do not require any whitespace around the operator. and= and or= however do require whitespace since they're English. Therefore, extract those two into their own pattern with proper boundary checking (identifier + spaces, or no identifier before the operator).

Alternate Designs

None.

Benefits

operand=, editor= will be tokenized correctly.

Possible Drawbacks

None.

Applicable Issues

Fixes #152