`clippy::format_collect`

Write into one String with write! or push_str instead of allocating one String per item.

What it reads

Clippy, with the compiler behind it. The only pass that compiles.

Lowest tier: real, and rarely urgent.

The tier bounds how severe a rule may be; its category bounds the tier.

Turn it off, or make it blocking, without touching the code it flags:

rust-doctor --rule clippy::format_collect=off .
rust-doctor --rule clippy::format_collect=error .