fix dupe word typos

compiler/rustc_lint/src/builtin.rs

@@ -1392,7 +1392,7 @@ fn check_attribute(&mut self, cx: &LateContext<'_>, attr: &ast::Attribute) {
     ///
     /// The attribute must be used in conjunction with the
     /// [`closure_track_caller` feature flag]. Otherwise, the `#[track_caller]`
-    /// annotation will function as as no-op.
+    /// annotation will function as a no-op.
     ///
     /// [`closure_track_caller` feature flag]: https://doc.rust-lang.org/beta/unstable-book/language-features/closure-track-caller.html
     UNGATED_ASYNC_FN_TRACK_CALLER,

compiler/rustc_lint/src/early.rs

@@ -29,7 +29,7 @@ macro_rules! lint_callback { ($cx:expr, $f:ident, $($args:expr),*) => ({
     $cx.pass.$f(&$cx.context, $($args),*);
 }) }
 
-/// Implements the AST traversal for early lint passes. `T` provides the the
+/// Implements the AST traversal for early lint passes. `T` provides the
 /// `check_*` methods.
 pub struct EarlyContextAndPass<'a, T: EarlyLintPass> {
     context: EarlyContext<'a>,

compiler/rustc_lint/src/late.rs

@@ -40,7 +40,7 @@ macro_rules! lint_callback { ($cx:expr, $f:ident, $($args:expr),*) => ({
     $cx.pass.$f(&$cx.context, $($args),*);
 }) }
 
-/// Implements the AST traversal for late lint passes. `T` provides the the
+/// Implements the AST traversal for late lint passes. `T` provides the
 /// `check_*` methods.
 pub struct LateContextAndPass<'tcx, T: LateLintPass<'tcx>> {
     context: LateContext<'tcx>,

src/librustdoc/visit_ast.rs

@@ -410,7 +410,7 @@ fn visit_foreign_item_inner(
 
     /// This method will create a new module and push it onto the "modules stack" then call
     /// `visit_mod_contents`. Once done, it'll remove it from the "modules stack" and instead
-    /// add into into the list of modules of the current module.
+    /// add into the list of modules of the current module.
     fn enter_mod(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>, name: Symbol) {
         self.modules.push(Module::new(name, id, m.spans.inner_span));