rustdoc: highlight macros more efficiently
rustdoc: highlight macros more efficiently

Instead of producing `<span class=macro>assert_eq</span><span class=macro>!</span>`,
just produce `<span class=macro>assert_eq!</span>`.

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