Auto merge of #27860 - m4rw3r:rustdoc_unstable_feature_issue, r=alexcrichton

Implemented #27759 

Example:

![screen shot 2015-08-16 at 21 45 17](https://cloud.githubusercontent.com/assets/108100/9295040/1fb24d50-4460-11e5-8ab8-81ac5330974a.png)

Author: bors

src/liballoc/lib.rs

@@ -69,6 +69,7 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
+       issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject))]
 #![no_std]
 #![cfg_attr(not(stage0), needs_allocator)]

src/libcollections/lib.rs

@@ -26,6 +26,7 @@
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
+       issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject))]
 
 #![allow(trivial_casts)]

src/libcore/lib.rs

@@ -58,7 +58,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
 #![doc(test(no_crate_inject))]
 
 #![no_core]

src/liblibc/lib.rs

@@ -21,7 +21,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
 #![cfg_attr(test, feature(test))]
 
 //! Bindings for the C standard library and other platform libraries

src/librustc_unicode/lib.rs

@@ -30,6 +30,7 @@
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
+       issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject))]
 #![no_std]
 

src/librustdoc/clean/mod.rs

@@ -2688,7 +2688,8 @@ pub struct Stability {
     pub feature: String,
     pub since: String,
     pub deprecated_since: String,
-    pub reason: String
+    pub reason: String,
+    pub issue: Option<u32>
 }
 
 impl Clean<Stability> for attr::Stability {
@@ -2702,6 +2703,7 @@ impl Clean<Stability> for attr::Stability {
                                                                     |istr| istr.to_string()),
             reason: self.reason.as_ref().map_or("".to_string(),
                                                 |interned| interned.to_string()),
+            issue: self.issue,
         }
     }
 }
@@ -2717,6 +2719,7 @@ impl<'a> Clean<Stability> for &'a attr::Stability {
                                                                     |istr| istr.to_string()),
             reason: self.reason.as_ref().map_or("".to_string(),
                                                 |interned| interned.to_string()),
+            issue: self.issue,
         }
     }
 }