Fix a spot I wrote the wrong word

Author: scottmcm

Diff for: compiler/rustc_middle/src/ty/sty.rs

@@ -2848,7 +2848,7 @@ impl<'tcx> Ty<'tcx> {
     /// Returning true means the type is known to be pure and `Copy+Clone`.
     /// Returning `false` means nothing -- could be `Copy`, might not be.
     ///
-    /// This is mostly useful for optimizations, as there are the types
+    /// This is mostly useful for optimizations, as these are the types
     /// on which we can replace cloning with dereferencing.
     pub fn is_trivially_pure_clone_copy(self) -> bool {
         match self.kind() {