rustdoc: do not write {{root}} in pub use ::foo docs

Author: notriddle

src/librustdoc/html/format.rs

@@ -18,6 +18,7 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::ty;
 use rustc_middle::ty::DefIdTree;
 use rustc_middle::ty::TyCtxt;
+use rustc_span::symbol::kw;
 use rustc_span::{sym, Symbol};
 use rustc_target::spec::abi::Abi;
 
@@ -679,7 +680,7 @@ fn resolved_path<'cx>(
 
     if print_all {
         for seg in &path.segments[..path.segments.len() - 1] {
-            write!(w, "{}::", seg.name)?;
+            write!(w, "{}::", if seg.name == kw::PathRoot { "" } else { seg.name.as_str() })?;
         }
     }
     if w.alternate() {

src/test/rustdoc/issue-95873.rs

@@ -0,0 +1,2 @@
+// @!has issue_95873/index.html '{{root}}'
+pub use ::std as x;