Auto merge of #5885 - Ryan1729:patch-2, r=flip1995
Auto merge of #5885 - Ryan1729:patch-2, r=flip1995

Add example of false positive to PTR_ARG docs.

Addresses #214

changelog: Add example of false positive to `ptr_arg` docs.

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