* BREAKING CHANGE: Correct definition of user_rounding_error,
To return correct type.
Likewise fix up a few other rounding error inconsistencies.
Fixes https://github.com/boostorg/math/issues/834.
* Remove redundant error handler.
Change error handlers to pass the target type down to "rounding errors".
Change the rounding error handlers to return a well defined value (the maximum representable value in the target type).
Update and complete docs on rounding errors.
Fix typo in test/test_beta_dist.cpp.
Regenerate the docs.
Remove illegal comment from test_constants.cpp.
Fixes#4977.
[SVN r67231]