These are all more or less plain text formats.

* The previous convention of !* ... *! are now true block comments,
  i.e. they are parsed faster, don't spam the goto table and allow
  embedding of exclamation marks - only "*!" terminates the comment.
* It is therefore now forbidden to have goto labels beginning with "*".
* Also support "!!" to introduce EOL comments (like C++'s //).
  This disallows empty labels, but they weren't useful anyway.
  This is the shortest way to begin a comment.
* All comment labels have been converted to true comments, to ensure
  that syntax highlighting works correctly.
  EOL comments are used for single line commented-out code, since it's
  easiest to uncomment - you don't have to jump to the line end.
  This is a pure convention / coding style.
  Other people might do it differently.
* It's of course still possible to abuse goto labels as comments
  as TECO did for ages.
* In lexing / syntax highlighting, labels and comments are highlighted differently.
* When syntax highlighting, a single "!" will first be highlighted as a label
  since it's not yet unambiguous. Once you type the second character (* or !),
  the first character is retroactively styled as a comment as well.

* We cannot call it "." since that introduces a local register
  and we don't want to add an unnecessary syntactic exception.
* Allows the idiom [: ... ]: to temporarily move around.
  Also, you can now write ^E\: without having to store dot in a register first.
* In the future we might add an ^E register as well for byte offsets.
  However, there are much fewer useful applications.
* Of course, you can now also write nU: instead of nJ, Q: instead of "." and
  n%: instead of "nC.". However it's all not really useful.

* Curses: "icons" have also been added

It's not a real Lexilla lexer, but simply styles the document
once in lexer.set.git in order to highlight comment lines.