Fix for a new rapply tactic

[JasonGross]

This backwards compatible change makes math-classes work with coq/coq#10760 by replacing all instances of rapply which were relying on typeclass resolution happening before refine (instead of simultaneously with it) to instead invoke Tactics.rapply (which is the same tactic in Coq <= 8.10, and which will be the tactic rather than the uconstr-taking tactic notation in Coq >= 8.11).

See also https://github.com/coq/coq/pull/10760#issuecomment-532399518

For reference, this changes 9 of the 34 invocations of rapply.

[Zimmi48]

Note that while this patch does no harm, it is not clear yet whether coq/coq#10760 will be merged as is, and thus whether it will be necessary.

[spitters]

I'm fine with the changes, but propose to wait until the discussion in coq/coq#10760 stabilizes.