rustdoc: Moved `SCHEMA_VERSION` to `clean`.

it should be changed when the module gets updated, so it helps to
have the `SCHEMA_VERSION` with the definitions themselves.

src/librustdoc/clean.rs

@@ -32,6 +32,10 @@
 use doctree;
 use visit_ast;
 
+/// A stable identifier to the particular version of JSON output.
+/// Increment this when the `Crate` and related structures change.
+pub static SCHEMA_VERSION: &'static str = "0.8.2";
+
 pub trait Clean<T> {
     fn clean(&self) -> T;
 }

src/librustdoc/lib.rs

@@ -34,6 +34,9 @@
 use std::str;
 use serialize::{json, Decodable, Encodable};
 
+// reexported from `clean` so it can be easily updated with the mod itself
+pub use clean::SCHEMA_VERSION;
+
 pub mod clean;
 pub mod core;
 pub mod doctree;
@@ -55,8 +58,6 @@ pub mod html {
 pub mod test;
 mod flock;
 
-pub static SCHEMA_VERSION: &'static str = "0.8.1";
-
 type Pass = (&'static str,                                      // name
              fn(clean::Crate) -> plugins::PluginResult,         // fn
              &'static str);                                     // description