Fix intra-doc link issues exposed by new macro

These links never worked, but the lint was suppressed due to the fact
that the span was pointing into the macro. With the new macro
implementation, the span now points directly to the doc comment in the
macro invocation, so it's no longer suppressed.

compiler/rustc_middle/src/mir/mod.rs

@@ -1847,6 +1847,7 @@ rustc_index::newtype_index! {
     /// rustc can identify that a field projection refers to either two different regions of memory
     /// or the same one between the base and the 'projection element'.
     /// Read more about projections in the [rustc-dev-guide][mir-datatypes]
+    ///
     /// [wrapper]: https://rustc-dev-guide.rust-lang.org/appendix/glossary.html#newtype
     /// [CFG]: https://rustc-dev-guide.rust-lang.org/appendix/background.html#cfg
     /// [mir-datatypes]: https://rustc-dev-guide.rust-lang.org/mir/index.html#mir-data-types

compiler/rustc_mir_transform/src/coverage/graph.rs

@@ -281,7 +281,7 @@ impl graph::WithPredecessors for CoverageGraph {
 }
 
 rustc_index::newtype_index! {
-    /// A node in the [control-flow graph][CFG] of CoverageGraph.
+    /// A node in the control-flow graph of CoverageGraph.
     pub(super) struct BasicCoverageBlock {
         DEBUG_FORMAT = "bcb{}",
         const START_BCB = 0,