Add class method signatures to TransalationContext

[thanhnguyen-aws]

Description of changes: This PR add Class method signatures into TransalationContext, so inputs (positional & keyword args) of the calls of those methods are parsed correctly.

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[joehendrix]

Are there any additional tests we can add to catch regressions? Also can the call site that uses this information to throw an error rather than generate Laurel that will fail typechecking.

[thanhnguyen-aws]

Are there any additional tests we can add to catch regressions? Also can the call site that uses this information to throw an error rather than generate Laurel that will fail typechecking.
I add a check in line 832. It will throw an error if a function is called with keyword args but missing signature in TranslationContext.

[joehendrix]

I'd be good to add a regression test to catch the new error.