comment plugin: add comment syntax for Factor

[AndydeCleyre]

Simply adds the comment symbol used by Factor, !, to the comment plugin.

[Andriamanitra]

Micro currently does not recognize "factor" file type so this change alone does not do much. It would be good to add a syntax file as well to detect the file type.

[AndydeCleyre]

I'm using one locally but it's not polished enough to contribute:

filetype: factor

detect:
    filename: "\\.factor(-rc)?$"

rules:
    - comment: "!.*$"
    - comment: "/\\*.*\\*/"
    - symbol.operator: "\\[|\\]|\\(|\\)|\\{|\\}|;|--|:|>>"  # Added curly braces and colon
    - constant.string: "\".*\""
    - constant: "\\b(t|f)\\b"
    - type: "\\b[A-Z][A-Z0-9_-]*:\\b"  # All-caps words ending with colon
    - type: "\\b(USING:|IN:|FROM:|QUALIFIED:|ALIAS:|RENAME:)\\b"
    - statement: "\\b(2nip|2dup|2drop|2bi|2tri|2curry|2dip|2keep|2over|3bi|3curry|3dip|3drop|3dup|3keep|3tri|4dip|4drop|4dup|4keep|deep-clone|keep-under|bi-curry|clone|\\?execute|\\?if|and|assert|assert=|assert\\?|bi-curry|bi@|bi\\*|boolean|call|clear|compose|curry|die|dip|do|drop|dup|execute|if|keep|loop|new|nip|not|null|object|or|over|pick|rot|swap|throw|unless|until|when|while|with|wrapper)\\b"
    - identifier: "^:\\s+[\\w-]+\\b"
    - constant.number: "\\b[0-9]+\\b"

If anyone else wants to have a go, for reference here are some existing regex-based syntax highlighting definitions for Factor:

• highlight
• vim