Minor bug in error message maps:update

[ThomasArts]

Describe the bug
The error message returned from maps:update is misleading.

To Reproduce
Open an Erlang shell. Type:

2> maps:update(u, 1, #{}).
** exception error: bad key: u
     in function  maps:update/3
        called as maps:update(u,1,#{})
        *** argument 3: not a map

Indeed, the key is a bad, key, but I would argue that the 3rd argument is a valid map.
This is not just for the empty map, but even for:

3> maps:update(u, 1, #{c => 1}).
** exception error: bad key: u
     in function  maps:update/3
        called as maps:update(u,1,#{c => 1})
        *** argument 3: not a map

Expected behavior
I expect the error message not to complain about the actual third argument.

Affected versions
The OTP versions that are affected by this bug.
Tested this on OTP-26.2.5.

[jhogberg]

Thanks for your report, I've fixed it in #8721 :-)