tweak fmt::Arguments docs
tweak fmt::Arguments docs

Remove an outdated claim about passing something or other to a function. Also swap the variable names in the example.
aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust