[ASTDumper] Use consistent coloring.

[dan-zheng]

• Use consistent coloring for closing parentheses.
  Some colored open parentheses (printed by printCommon) had uncolored closing parenthesis counterparts. Now, all such closing parentheses are colored.

• Use consistent coloring for ValueDecls (decl=).
  Most instances of decl=were printed with color but some were not.
  Now, all instances of decl= (and the subsequent ValueDecl or ConcreteDeclRef) are printed with color.

• Miscellaneous.
  Print assign_expr with color (using printCommon).
  Print function_ref for UnresolvedDotExpr with color, to be consistent with all other function_ref printing.

[dan-zheng]

I don't believe there are tests for ASTDumper output.

Below is an image showing some before/after changes (before on left, after on right, changes are boxed).

// test.swift
struct S {
  let int: Int
}

let a = (1, 2, 3)
a.0

#selector(MyViewController.tappedButton)

I ran swiftc -dump-ast test.swift before and after.

[dan-zheng]

@swift-ci Please smoke test

[CodaFi]

Thanks!

⛵️