Attempt to improve the `std::fs::create_dir_all` docs related to atomicity
The original paragraph was added in rust-lang/rust#124520. It doesn't match the actual code logic. It says "function returns an error" if "the parent components" _(which also implies directories)_ "have been created already". The code is as follows:
e88e854634/library/std/src/fs.rs (L3146)e88e854634/library/std/src/fs.rs (L3160)
These lines suppress all errors if any path component is a directory. I've updated the paragraph to mirror this.
a49ae1c40f