Rollup merge of #77701 - jyn514:debug-logging, r=Mark-Simulacrum
Rollup merge of #77701 - jyn514:debug-logging, r=Mark-Simulacrum

Make `max_log_info` easily greppable (for figuring out why debug logging is disabled)

Follow-up to https://github.com/rust-lang/rust/pull/77678#issuecomment-705545608. I'll make a PR to the dev-guide shortly changing `debug = true` to `debug-logging = true` and using this text.

Ideally wouldn't be merged before https://github.com/rust-lang/rust/pull/77678, but it practice it won't hurt anything.

r? @Mark-Simulacrum

graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust