This commit adds a lexer for NES Assembly.

The json-doc lexer inherits from the JSON lexet. As a consequence, an
earlier refactoring of the JSON lexer that, among other things,
introduced two new states broke the json-doc lexer. This commit corrects
the references to these states.

This commit adds the `_finally` keyword to the Magik lexer.

The current TOML lexer does not support inline tables. This commit fixes
that by adding a new `:inline` state.

This commit adds a lexer for the Slice language.

This commit corrects 'exited' to 'excited'.

The Shopify Liquid parser and the Jekyll Liquid parser treat the
argument to the `include` tag differently. Specifically, the Jekyll
lexer expects a filepath.

The existing Liquid lexer does not properly handle code written for the
Jekyll implementation. This commit fixes that by introducing a rule thet
matches against slashes, periods and alphanumeric characters.

A number of lexers included a newline at the end of the pattern for
matching comments. This would result in a comment not being lexed
correctly if it was at the end of text. This commit fixes numerous
instances of this.