[mlir] minor documentation fix in GPUTransformOps.td (#121157)

- do not refer to handles as `PDLOperation`, this is an outdated and
incorrect vision of what they are based on the type used in the early
days;
 - use backticks around inline code.

mlir/include/mlir/Dialect/GPU/TransformOps/GPUTransformOps.td

@@ -168,13 +168,13 @@ def MapNestedForallToThreads :
 
       #### Return modes:
 
-      This operation ignores non-gpu_launch ops and drops them in the return.
+      This operation ignores non-`gpu_launch` ops and drops them in the return.
 
       If any scf.forall with tensors is found, the transform definitely
       fails.
 
-      If all the scf.forall operations with gpu.thread mapping contained
-      within the LaunchOp referred to by the `target` PDLOperation lower to GPU
+      If all the `scf.forall` operations with gpu.thread mapping contained
+      within the `LaunchOp` referred to by the `target` handle lower to GPU
       properly, the transform succeeds. Otherwise the transform definitely
       fails.
 
@@ -277,8 +277,8 @@ def MapForallToBlocks :
     If any scf.forall with tensors is found, the transform definitely
     fails.
 
-    If all the scf.forall operations contained within the LaunchOp
-    referred to by the `target` PDLOperation lower to GPU properly, the
+    If all the `scf.forall` operations contained within the LaunchOp
+    referred to by the `target` handle lower to GPU properly, the
     transform succeeds. Otherwise the transform definitely fails.
 
     The returned handle points to the same LaunchOp operand, consuming it and