Add parameter reference tag

A DESCRIPTION OF THE PROBLEM :
It would be useful if there was a Java doc tag which allows referencing a parameter of a method or constructor in its documentation, e.g.:

/**
 * Creates a sub string starting at {@param startIndex} (inclusive).
 *
 * @param startIndex Index at which sub string should start
 * @return sub string
 */
String subString(int startIndex);

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This would make it easier for IDEs to refactor parameter names. With the current solution of using `{@code myParam}` this might not be possible or could be ambiguous.
It could also make it easier to understand that a paramter is referenced when reading a doc.

I am not sure about the HTML formatting to apply, maybe italic code would be good to differentiate it from normal code:
{@param myParam} -> <code><i>myParam</i></code>