rustdoc: Migrate from sundown to hoedown

This primary fix brought on by this upgrade is the proper matching of the ```
and ~~~ doc blocks. This also moves hoedown to a git submodule rather than a
bundled repository.

Additionally, hoedown is stricter about code blocks, so this ended up fixing a
lot of invalid code blocks (ending with " ```" instead of "```", or ending with
"~~~~" instead of "~~~").

Closes #12776

5 files changed, 8 insertions, 8 deletions

diff --git a/src/libstd/c_str.rs b/src/libstd/c_str.rs
index 310bc861cd3..7de74dbe507 100644
--- a/src/libstd/c_str.rs
+++ b/src/libstd/c_str.rs
@@ -61,7 +61,7 @@ fn main() {
         unsafe { puts(c_buffer); }
     });
 }
- ```
+```
 
 */
 
diff --git a/src/libstd/iter.rs b/src/libstd/iter.rs
index 18532c39443..62088e5b646 100644
--- a/src/libstd/iter.rs
+++ b/src/libstd/iter.rs
@@ -52,7 +52,7 @@ loop {
         None => { break }
     }
 }
- ```
+```
 
 This `for` loop syntax can be applied to any iterator over any type.
 
diff --git a/src/libstd/local_data.rs b/src/libstd/local_data.rs
index a6199aa43ab..072884a1f74 100644
--- a/src/libstd/local_data.rs
+++ b/src/libstd/local_data.rs
@@ -33,7 +33,7 @@ local_data::get(key_int, |opt| assert_eq!(opt.map(|x| *x), Some(3)));
 
 local_data::set(key_vector, ~[4]);
 local_data::get(key_vector, |opt| assert_eq!(*opt.unwrap(), ~[4]));
- ```
+```
 
 */
 
diff --git a/src/libstd/slice.rs b/src/libstd/slice.rs
index 64f6b59be24..43159bcb44a 100644
--- a/src/libstd/slice.rs
+++ b/src/libstd/slice.rs
@@ -19,7 +19,7 @@ homogeneous types:
 ```rust
 let int_vector = [1,2,3];
 let str_vector = ["one", "two", "three"];
- ```
+```
 
 This is a big module, but for a high-level overview:
 
@@ -44,7 +44,7 @@ a vector or a vector slice from the index interval `[a, b)`:
 let numbers = [0, 1, 2];
 let last_numbers = numbers.slice(1, 3);
 // last_numbers is now &[1, 2]
- ```
+```
 
 Traits defined for the `~[T]` type, like `OwnedVector`, can only be called
 on such vectors. These methods deal with adding elements or otherwise changing
@@ -57,7 +57,7 @@ of the vector:
 let mut numbers = vec![0, 1, 2];
 numbers.push(7);
 // numbers is now vec![0, 1, 2, 7];
- ```
+```
 
 ## Implementations of other traits
 
@@ -79,7 +79,7 @@ let numbers = [0, 1, 2];
 for &x in numbers.iter() {
     println!("{} is a number!", x);
 }
- ```
+```
 
 * `.mut_iter()` returns an iterator that allows modifying each value.
 * `.move_iter()` converts an owned vector into an iterator that
diff --git a/src/libstd/str.rs b/src/libstd/str.rs
index b105dd0ca5a..adb0c299876 100644
--- a/src/libstd/str.rs
+++ b/src/libstd/str.rs
@@ -37,7 +37,7 @@ fn main() {
     let borrowed_string1 = "This string is borrowed with the 'static lifetime";
     let borrowed_string2: &str = owned_string;   // owned strings can be borrowed
 }
- ```
+```
 
 From the example above, you can see that Rust has 2 different kinds of string
 literals. The owned literals correspond to the owned string types, but the