Changes:
- Add new missing keywords: https://doc.rust-lang.org/edition-guide/rust-2018/module-system/raw-identifiers.html#new-keywords
- Update the list of traits, with all core and std traits, obtained from the Rust documentation.
- Add keywords of constants.
- Remove duplicate keywords in different lists (such as self, Self and type).
- Highlight all symbols with the "Symbol" attribute.
- Highlight Raw identifier prefix (r#identifier).
- Highlight comments within definitions of functions and types.
- Correct indentation in some parts of the code and add modeline to avoid incorrect indentation (the file uses Tabs).
Sources: