Temporary patch to accept arbitrary lifetimes (behind feature gate) in bound lists. This is needed to bootstrap fix for #5723.

src/librustdoc/clean.rs

@@ -350,7 +350,8 @@ pub enum TyParamBound {
 impl Clean<TyParamBound> for ast::TyParamBound {
     fn clean(&self) -> TyParamBound {
         match *self {
-            ast::RegionTyParamBound => RegionBound,
+            ast::StaticRegionTyParamBound => RegionBound,
+            ast::OtherRegionTyParamBound(_) => RegionBound,
             ast::TraitTyParamBound(ref t) => TraitBound(t.clean()),
         }
     }