Rolling up PRs in the queue

Closes #13441 (debuginfo: Fixes and improvements for #12840, #12886, and #13213)
Closes #13433 (Remove references to @Trait from a compiler error message)
Closes #13430 (Fix outdated lint warning about inner attribute)
Closes #13425 (Remove a pile of (mainly) internal `~[]` uses)
Closes #13419 (Stop using transmute_mut in RefCell)
Closes #13417 (Remove an unnecessary file `src/libnative/io/p`.)
Closes #13409 (Closing assorted resolve bugs)
Closes #13406 (Generalized the pretty-print entry points to support `-o <file>`.)
Closes #13403 (test: Add a test for #7663)
Closes #13402 (rustdoc: Prune the paths that do not appear in the index.)
Closes #13396 (rustc: Remove absolute rpaths)
Closes #13371 (Rename ast::Purity and ast::Impure Function. Closes #7287)
Closes #13350 (collections: replace all ~[T] with Vec<T>.)