This converts the instances of the pattern for which we have a proper
substitution in lit. This will make it easier to replace it
appropriately with Windows equivalents.
NameMatcher checked if a StringLiteralExpr was a string segment in an
interpolated string by checking if the parent expression was an
InterpolatedStringLiteralExpr. That's only true pre-type-checking, and unlike
global rename, local rename uses the type-checked AST.
