Show javadocs/other information on hover

[OroArmor]

Showing javadocs on hover would be really helpful for reading what functions do. Even if there are no docs, it would be helpful to see what the parameter names are (and somehow if they are mapped) and what the return type is.

It would also allow seeing library names for parameters and understand what the code for them is doing, especially if libraries had their javadocs indexed.

[ix0rai]

this should be possible using #156 !
the swing wizardry might be tough, but it should definitely be doable by indexing javadocs