Remove ~str constructors

[brson]

Per https://mail.mozilla.org/pipermail/rust-dev/2014-April/009519.html

cc #12938

Nominating.

[richo]

I'm interested in helping with this as a fairly easy (read: repetitive) way to dip my toes into rust's core.

[brson]

@richo ok! @pcwalton was planning on working on this too (but I'm sure he would appreciate help), so I suggest going in small incremental chunks to avoid clashing with each other.

I think all that has to be done here is convert everything that looks like ~"foo" to "foo".to_owned().

[brson]

Note that I originally titled this bug incorrectly. We don't actually need to convert to StrBuf unless the code is building a string.

[richo]

Ah, ok.

The first change is easy- I'll look at call sites though to see if using StrBuf makes more sense.

[richo]

This looks like I can automate it pretty easily. I'll get a PR in tonight /cc @pcwalton

[brson]

Let's also remove the language support, since DST changes the semantics.

1.0 backcompat lang.

[pcwalton]

Closed by #13877!