Unicode_Entities: Support for using Unicode entity names for characters

Julia Version	Unit Tests	Coverage

Unicode_Entities.jl

This builds tables for looking up Unicode entity names and returning the Unicode character(s), looking up a character or pair of characters and finding Unicode entity names that return it/them, and finding all of the Unicode name completions for a particular string, if any.

Version 1.1.x is based on Unicode version 13.0.0 Version 1.2.x is based on Unicode version 14.0.0