Warn against using legacy std integral constants

[pitaj]

What it does

This lint triggers on usage of legacy integral constants and functions, such as:

• std::i32::MAX
• u64::max_value()

Advantage

Enforce a consistent style across the ecosystem.

This lint should probably be placed into the clippy::style group.

Drawbacks

Older projects will experience some churn, but this should be trivially auto-fixable in most cases.

T-libs-api opposes deprecating this outright so a clippy lint is the next best thing.

Example

if x == std::i32::MAX {

Could be written using the associated constant as:

if x == i32::MAX {

[xFrednet]

The PR was closed due to inactivity, if anyone is interested in picking up this issue, that PR would be a good starting point. We also discussed, how the lint should behave in that PR.