Improve error message for StreamReadConstraints violations

[cowtowncoder]

Currently (as of 2.15.0), violation of StreamReadConstraints is indicated by message like:

String length (50000001) exceeds the maximum length (5000000)

which does not much indication as to where the setting might be defined or changeable.
Let's add some more information; for example:

String value length (50000001) exceeds the maximum length (5000000 from `StreamReadConstraints.getMaxStringLength()`)

NOTE: not adding in 2.15.1 since Exception messages are part of API and while this seems generally useful I want to avoid potential breakage in patch release. But at the same time it's a minor change so do not think it requires waiting for major version (since timing of 3.0 is still unclear).