Updating str.chars docs to mention crates.io.
Updating str.chars docs to mention crates.io.

This might spare someone else a little time searching the stdlib for unicode/grapheme support.
aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust