Adopt "deprecated" API

[spahnke]

Adopts tags to mark elements as deprecated in diagnostics and suggestion items so that they can be rendered with a strikethrough syle.

Editor and suggestion item:

I also added tags (e.g. @param, @deprecated) to the documentation of suggestion items. This helps to discover alternatives to deprecated items if they are documented appropriately:

Finally I aligned the representation of tags in suggestion documentation and hover information (this existed before and I replaced it with the new logic). Let me know if this is OK. I tried to adopt the representation of VS Code as far as @param tags are concerned, where the parameter name is represented as code and the actual documentation text is appended with a separation character:

Example code:

class Test {
	/**
	 * asdf
	 * @param {number} a testing `code`
	 * @param {number} b testing more `code`
	 * @deprecated use `bar` instead
	 */
	foo(a, b) { }

	bar(a, b) { }
}

new Test().foo(1, 2);

/** @deprecated use that other function instead */
function test() { }

test()

[alexdima]

This is great, thank you!