Feature request: automatically replace texas ops with unicode equivalents

[AlexDaniel]

This ticket is inspired by reddit comments.

Example: you type <=, it should automatically replaces it with ≤. Obviously, make it possible to turn that feature off, but perhaps consider having it enabled by default.

List of non-texas ops: https://docs.perl6.org/language/unicode_texas

Sister tickets:

• atom-language-perl6
• vim-perl6