Prelude: rename and consolidate extension traits

This commit renames a number of extension traits for slices and string
slices, now that they have been refactored for DST. In many cases,
multiple extension traits could now be consolidated. Further
consolidation will be possible with generalized where clauses.

The renamings are consistent with the [new `-Prelude`
suffix](https://github.com/rust-lang/rfcs/pull/344). There are probably
a few more candidates for being renamed this way, but that is left for
API stabilization of the relevant modules.

Because this renames traits, it is a:

[breaking-change]

However, I do not expect any code that currently uses the standard
library to actually break.

Closes #17917

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/rand/reader.rs b/src/libstd/rand/reader.rs
index c1bb6970f71..c8ed9805215 100644
--- a/src/libstd/rand/reader.rs
+++ b/src/libstd/rand/reader.rs
@@ -13,7 +13,7 @@
 use io::Reader;
 use rand::Rng;
 use result::{Ok, Err};
-use slice::ImmutableSlice;
+use slice::SlicePrelude;
 
 /// An RNG that reads random bytes straight from a `Reader`. This will
 /// work best with an infinite reader, but this is not required.