Investigate alternative to hover-bubble

[brancz]

We've had a user report that in the case of Rust binaries, symbols can be very very long:

Here are this the concrete symbol shown in the screenshot: https://gist.github.com/brancz/2913d114a5eccb0ecb2ab04e92791d1e

And the DWARF entry looks like this: https://gist.github.com/brancz/f47cda1e0f3eb358068ece6a5ed66c1e

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I don't know what the best thing is to solve this, but the user mentioned that it's useful to at least have the possibility to see the full and demangled name. By default, we could display something along the lines of:

<timely::dataflow::operators::generic::builder_raw::OperatorCore<T> as timely::scheduling::Schedule>::schedule

(which is the demangled name with the first occurrence of a generic type parameter elided)

That could be a solution for a start so we can display something, but long term we should figure out a way to display the full string somewhere in the UI.

One solution could be to have a sidebar instead of the hover bubble to display the additional information.

[yomete]

Safe to say this has been possibly fixed by the option to dock the tooltip? @brancz