Syntax highlighting for Thymeleaf test (.thtest) files

[ultraq]

Create a new editor for the .thtest file extension, adding syntax highlighting, code completion, and all those goodies for Thymeleaf testing files.

This will probably be a massive task - I'll need to break it up into smaller pieces.

[danielfernandez]

Oh yes! yes yes yes yes! Do want! ;-);-)

[tduchateau]

:+1: :-)

[danielfernandez]

By the way, you might be able to use parts of the test file parsing logic in https://github.com/thymeleaf/thymeleaf-testing/blob/thymeleaf-testing-2.0.2/src/main/java/org/thymeleaf/testing/templateengine/standard/test/reader/StandardTestReader.java

[ultraq]

Doing some spring cleaning of issues, and I'm going to close this one - it's been open for over a decade so highly unlikely we'll get do this 😅