The `__future__` we relied on is now, where the 3 specific things are
all included [since Python 3.0](https://docs.python.org/3/library/__future__.html):
* absolute_import
* print_function
* unicode_literals
* division
These import statements are no-ops and are no longer necessary.
* [Parser] Update 'Confusables.def' file to include confusable and base character names
* [Parser] Add a new utility method to return the names of the confusable and base characters for a given confusable codepoint
* [Parser] Update diagnostic for confusable character during lexing to mention confusable and base character names
* [Sema] If there is just a single confusable character, emit a tailored diagnostic that also mentions the character names
* [Diagnostics] Add new diagnostic messages to the localization file
* [Test] Update confusables test
* [Utils] Update unicode confusables txt file and update script to regenerate confusables def file
* [Parse] Regenerate 'Confusables.def' using updated script
* [Utils] Adjust generate_confusables script based on review feedback
Fix a mistake with name mapping. Updated header comment. Fix a couple of linting issues.
* [Parse] Regenerate 'Confusables.def' file once again after script changes
* [Parse] Add the newline after end of 'getConfusableAndBaseCodepointNames' method
* [Test] Update diagnostic message in 'Syntax/Parser/diags.swift'
