fix/extend some comments

Author: RalfJung

src/tools/miri/src/intrinsics/mod.rs

@@ -91,14 +91,15 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
 
         match intrinsic_name {
+            // Basic control flow
             "abort" => {
                 throw_machine_stop!(TerminationInfo::Abort(
                     "the program aborted execution".to_owned()
                 ));
             }
             "catch_unwind" => {
                 this.handle_catch_unwind(args, dest, ret)?;
-                // THis pushed a stack frame, don't jump to `ret`.
+                // This pushed a stack frame, don't jump to `ret`.
                 return Ok(EmulateItemResult::AlreadyJumped);
             }