body matcher gives no details when assertion fails

[Daniel Jowett]

Is there a reason that the AssertionError in the body matcher does not supply details of the error?

It is difficult to determine some test failures without it.

This is an example of my current test output.

Matchers succeeded : ['method', 'scheme', 'host', 'port', 'path', 'query']
Matchers failed :
headers - assertion failure :
{'Accept-Encoding': 'gzip, deflate, br', 'Accept': '*/*', 'Connection': 'keep-alive', 'Content-Length': '889', 'Content-Type': 'application/json'} != {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate, br', 'Connection': 'keep-alive', 'Content-Length': '888', 'Content-Type': 'application/json'}
body - assertion failure :

(this also applies to the raw_body matcher)

I believe this was not the case before #644

If there's no good reason to avoid it, I can provide a PR to re-add it.