Auto merge of #4315 - phansch:fn_to_numeric_cast_applicability, r=flip1995
Auto merge of #4315 - phansch:fn_to_numeric_cast_applicability, r=flip1995

Mark `fn_to_numeric_cast` lints as MaybeIncorrect

At least for now so that `cargo fix --clippy` is not causing problems
with this lint. See #3896 for the remaining problems with the suggestions of this lint.

changelog: none

cc #3630, #3896

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