Clarified the attribute which prompts the warning
Clarified the attribute which prompts the warning

The example call was lacking clarification of the  `#![warn(rustdoc::invalid_codeblock_attributes)]` attribute which generates the specified warning.
graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust