auto merge of #13812 : alxgnon/rust/master, r=alexcrichton

This is a quick fix for repeated documentation descriptions in certain modules.
Following is a list of the faulty modules I found. I ran `pcregrep -r -M "<p>(.+)\n\1" doc` on the html documentation to help identify them.

- [rustuv::uvio](http://static.rust-lang.org/doc/master/rustuv/uvio/index.html)
- [rustuv::uvll](http://static.rust-lang.org/doc/master/rustuv/uvll/index.html)
- [std::rt::backtrace](http://static.rust-lang.org/doc/master/std/rt/backtrace/index.html)
- [std::rt::env](http://static.rust-lang.org/doc/master/std/rt/env/index.html)
- [std::rt::global_heap](http://static.rust-lang.org/doc/master/std/rt/global_heap/index.html)
- [std::rt::local_heap](http://static.rust-lang.org/doc/master/std/rt/local_heap/index.html)
- [std::rt::rtio](http://static.rust-lang.org/doc/master/std/rt/rtio/index.html)
- [std::rt::task](http://static.rust-lang.org/doc/master/std/rt/task/index.html)
- [std::rt::thread](http://static.rust-lang.org/doc/master/std/rt/thread/index.html)
- [std::rt::unwind](http://static.rust-lang.org/doc/master/std/rt/unwind/index.html)
- [syntax::parse::classify](http://static.rust-lang.org/doc/master/syntax/parse/classify/index.html)
- [syntax::parse::common](http://static.rust-lang.org/doc/master/syntax/parse/common/index.html)

After a little testing, I discovered that moving the documentation inside (`//!`) instead of outside (`///`) modules fixed the immediate problem. I went through the trouble of moving the documentation, and with this commit there are no more repeated descriptions within those faulty modules.

This does not fix the underlying problem though. We should look into why having the documentation outside instead of inside caused the descriptions to be repeated. I will create a separate issue with my findings on the subject if necessary.
In the meantime, this simple fix should be enough.

5 files changed, 23 insertions, 14 deletions

diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index 85699cdfebc..26494f1acd9 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+//! Simple backtrace functionality (to print on failure)
+
 #![allow(non_camel_case_types)]
 
 use char::Char;
diff --git a/src/libstd/rt/global_heap.rs b/src/libstd/rt/global_heap.rs
index 01949a7057b..b9c0a02d7d2 100644
--- a/src/libstd/rt/global_heap.rs
+++ b/src/libstd/rt/global_heap.rs
@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+
+//! The global (exchange) heap.
+
 use libc::{c_void, size_t, free, malloc, realloc};
 use ptr::{RawPtr, mut_null};
 use intrinsics::abort;
diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index a61443d335a..b407bf8897c 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -85,44 +85,44 @@ pub mod shouldnt_be_public {
 // Internal macros used by the runtime.
 mod macros;
 
-/// The global (exchange) heap.
+// The global (exchange) heap.
 pub mod global_heap;
 
-/// Implementations of language-critical runtime features like @.
+// Implementations of language-critical runtime features like @.
 pub mod task;
 
-/// The EventLoop and internal synchronous I/O interface.
+// The EventLoop and internal synchronous I/O interface.
 pub mod rtio;
 
-/// The Local trait for types that are accessible via thread-local
-/// or task-local storage.
+// The Local trait for types that are accessible via thread-local
+// or task-local storage.
 pub mod local;
 
-/// Bindings to system threading libraries.
+// Bindings to system threading libraries.
 pub mod thread;
 
-/// The runtime configuration, read from environment variables.
+// The runtime configuration, read from environment variables.
 pub mod env;
 
-/// The local, managed heap
+// The local, managed heap
 pub mod local_heap;
 
-/// The runtime needs to be able to put a pointer into thread-local storage.
+// The runtime needs to be able to put a pointer into thread-local storage.
 mod local_ptr;
 
-/// Bindings to pthread/windows thread-local storage.
+// Bindings to pthread/windows thread-local storage.
 mod thread_local_storage;
 
-/// Stack unwinding
+// Stack unwinding
 pub mod unwind;
 
-/// The interface to libunwind that rust is using.
+// The interface to libunwind that rust is using.
 mod libunwind;
 
-/// Simple backtrace functionality (to print on failure)
+// Simple backtrace functionality (to print on failure)
 pub mod backtrace;
 
-/// Just stuff
+// Just stuff
 mod util;
 
 // Global command line argument storage
diff --git a/src/libstd/rt/rtio.rs b/src/libstd/rt/rtio.rs
index f3c7fdaf710..fc8c79549af 100644
--- a/src/libstd/rt/rtio.rs
+++ b/src/libstd/rt/rtio.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+//! The EventLoop and internal synchronous I/O interface.
+
 use c_str::CString;
 use cast;
 use comm::{Sender, Receiver};
diff --git a/src/libstd/rt/unwind.rs b/src/libstd/rt/unwind.rs
index 68d63949ae6..4f84202f8f8 100644
--- a/src/libstd/rt/unwind.rs
+++ b/src/libstd/rt/unwind.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+//! Stack unwinding
+
 // Implementation of Rust stack unwinding
 //
 // For background on exception handling and stack unwinding please see