[scopes] Handle edge-case mappings that come up in TS and other misc bugs

[loganfsmyth]

Refs Issue: #5561

Summary of Changes

• A few misc bugs and generalizations for the mapping logic
• Properly distinguish TS and TSX files so they parse well
• When mapping original declarations, also find original location of the declaration itself and attempt to use that location as one option for applicable bindings
  • This allows TS class declarations to be mapped properly.

These changes have two major effects, as visible in the screenshots below:

• Declaration names that mapped to export.Foo = Foo; instead of the declaration are given lower priority to hopefully avoid mapping a binding to the whole exports object (the {...}) in the shots below
• Declarations with decorators now map to the declaration instead of decorator-related output

Screenshots/Videos (OPTIONAL)

Behavior previously:

With this PR: