Intelligently convert C/C++ comments to Rust

With this change, we can correctly parse C++ block comments.

```
/**
 * Does a thing
 *
 * More documentation. This test does something
 * useful.
 */
```

into

```
/// Does a thing
///
/// More documentation. This test does something
/// useful.
```

Fixes servo/rust-bindgen#426.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/ir/function.rs b/src/ir/function.rs
index 9865997d..299bd65c 100644
--- a/src/ir/function.rs
+++ b/src/ir/function.rs
@@ -1,5 +1,6 @@
 //! Intermediate representation for C/C++ functions and methods.
 
+use super::comment;
 use super::context::{BindgenContext, ItemId};
 use super::dot::DotAttributes;
 use super::item::Item;
@@ -405,7 +406,7 @@ impl ClangSubItemParser for Function {
             mangled_name = None;
         }
 
-        let comment = cursor.raw_comment();
+        let comment = cursor.raw_comment().map(comment::preprocess);
 
         let function = Self::new(name, mangled_name, sig, comment);
         Ok(ParseResult::New(function, Some(cursor)))