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, 2 insertions, 2 deletions

diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 49c688da31c..f5c6c15857a 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -18,7 +18,7 @@ use iter::ExactSize;
 use ops::Drop;
 use option::{Some, None, Option};
 use result::{Ok, Err};
-use slice::{ImmutableSlice, MutableSlice};
+use slice::{SlicePrelude};
 use slice;
 use vec::Vec;
 
@@ -376,7 +376,7 @@ mod test {
     use super::super::{IoResult, EndOfFile};
     use super::super::mem::{MemReader, MemWriter, BufReader};
     use self::test::Bencher;
-    use str::StrSlice;
+    use str::StrPrelude;
 
     /// A type, free to create, primarily intended for benchmarking creation of
     /// wrappers that, just for construction, don't need a Reader/Writer that