New lint: disallowed_types based on config

[DevinR528]

What it does

Check certain types are not used according to a config list (similar to disallowed_method).

Categories

• Nursery

Allow a project to specify types that are not allowed.

Drawbacks

None 🤷

Example

use std::collections::HashMap;

Could be written as:
possibly with a short explanation that is included in the config somehow?

// Since non of the maps will be large the cost of hashing is greater than the cost of lookup.
use std::collections::BTreeMap;

If everyone is ok with this in the nursery I can open a PR.

[jplatte]

A great example for where one would want to disallow HashMap (and HashSet) specifically is proc-macros, since hash maps introduce non-determinism, which is bad for caching.