Improve std::io::ErrorKind

[steveklabnik]

Hopefully make this distinction a little more clear.

Fixes #27637
r? @alexcrichton /cc @Havvy

[alexcrichton]

This seems like a bit of a step backwards to me by making InvalidInput a little more vague (generalizing "parameter" to "input state") and taking away the docs of InvalidData (which I think are basically saying the same thing). It may just be worth clarifying that InvalidData typically doesn't show up because of I/O errors perhaps?

[steveklabnik]

@alexcrichton I'm down. What do you think about this version?

[Havvy]

It literally reads to me as "IO errors will not cause this kind of IO Error Kind". Perhaps something of the line of "For example, a function that reads a file into a String will error with InvalidData if the file is not valid UTF-8."

[steveklabnik]

@Havvy sounds good, what about this revision?

[alexcrichton]

@bors: r+ 7c06c5a rollup

[bors]

⌛ Testing commit 7c06c5a with merge 3a407b6...

[alexcrichton]

Looks like our android bot is MIA but all tests passed so merging manually.