fix two comments

Author: lqd

compiler/rustc_borrowck/src/nll.rs

@@ -273,7 +273,7 @@ pub(super) fn dump_nll_mir<'tcx>(
         regioncx.dump_graphviz_raw_constraints(&mut file)?;
     };
 
-    // Also dump the inference graph constraints as a graphviz file.
+    // Also dump the inference graph constraints SCCs as a graphviz file.
     let _: io::Result<()> = try {
         let mut file = create_dump_file(infcx.tcx, "regioncx.scc.dot", false, "nll", &0, body)?;
         regioncx.dump_graphviz_scc_constraints(&mut file)?;

compiler/rustc_borrowck/src/region_infer/graphviz.rs

@@ -46,7 +46,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         dot::render(&RawConstraints { regioncx: self }, &mut w)
     }
 
-    /// Write out the region constraint graph.
+    /// Write out the region constraint SCC graph.
     pub(crate) fn dump_graphviz_scc_constraints(&self, mut w: &mut dyn Write) -> io::Result<()> {
         let mut nodes_per_scc: IndexVec<ConstraintSccIndex, _> =
             self.constraint_sccs.all_sccs().map(|_| Vec::new()).collect();