[beta] Smart completion and new JSDocs

Additions

• Added smart highlighting and syntax completion!
  Read more about it on the wiki
  This can be a pretty big improvement even if you don’t use other GMEdit features.
• Added a number of JSDoc tags!
  Similarly, they have their own wiki page
• Added auto-completion for JSDoc tags when typing @ in documentation comments.

Fixes

• Fixed zero-length physics point shape metadata in Object Properties being impossible to save.
• Fixed some cases where hexadecimal literals without proper delimiters could fool the indexer into thinking that they are variable names.
• Fixed a rather specific softlock in indexer when assigning macros into other macros.