Extend impure_functions list by socket functions

[alies-dev]

This prevents UnusedFunctionCall for some socket ext functions.

Result of all of these functions is boolean and can be ignored.

Note, socket errors can be fetched by:

• socket_strerror
• socket_last_error

Closes #8818

[orklah]

Thanks!

[danog]

Hmm this does not feel like a good idea, generally you should always check if a network operation failed or not, are we sure this is a good idea?

[alies-dev]

@danog
This is opinionated, agree.

In this PR I simply continues on what we already do here. Is it good a bad - it's a separate topic.
IMO ideally it should throw a new type of error, e.g. UnusedOptionalFunctionCallResult, so a user can easily suppress any such error.

[danog]

I see now that a bunch of other socket functions were already included in the list, and that the list is actually indicating impure functions, so this PR actually makes sense, as it is (correctly) indicating that these functions have side effects.

However, ignoring the result of at least the write, read, connect and bind functions is still an antipattern, it might be worth introducing an UnusedImpureFunctionCallResult issue for this case, yes.