[mlir][nfc] Update comments

1. Updates and clarifies a few comments related to hooks for
   vector.{insert|extract}_strided_slice.

2. For consistency with vector.insert_strided_slice, removes a TODO from
   vector.extract_strided_slice Op def. It's self-explenatory that
   adding support for non-unit strides is a "TODO".

Author: banach-space

mlir/include/mlir/Dialect/Vector/IR/VectorOps.td

@@ -1121,7 +1121,6 @@ def Vector_ExtractStridedSliceOp :
     attribute and extracts the n-D subvector at the proper offset.
 
     At the moment strides must contain only 1s.
-    // TODO: support non-1 strides.
 
     Returns an n-D vector where the first k-D dimensions match the `sizes`
     attribute. The returned subvector contains the elements starting at offset

mlir/lib/Dialect/Vector/IR/VectorOps.cpp

@@ -2789,9 +2789,11 @@ isIntegerArrayAttrConfinedToShape(OpType op, ArrayAttr arrayAttr,
   return success();
 }
 
-// Returns true if all integers in `arrayAttr` are in the interval [min, max}.
-// interval. If `halfOpen` is true then the admissible interval is [min, max).
-// Otherwise, the admissible interval is [min, max].
+// Returns true if, for all indices i = 0..shape.size()-1, val is in the
+// [min, max} interval:
+//   val = `arrayAttr1[i]` + `arrayAttr2[i]`,
+// If `halfOpen` is true then the admissible interval is [min, max). Otherwise,
+// the admissible interval is [min, max].
 template <typename OpType>
 static LogicalResult isSumOfIntegerArrayAttrConfinedToShape(
     OpType op, ArrayAttr arrayAttr1, ArrayAttr arrayAttr2,
@@ -2845,8 +2847,8 @@ LogicalResult InsertStridedSliceOp::verify() {
   auto stridesName = InsertStridedSliceOp::getStridesAttrName();
   if (failed(isIntegerArrayAttrConfinedToShape(*this, offsets, destShape,
                                                offName)) ||
-      failed(isIntegerArrayAttrConfinedToRange(*this, strides, 1, 1,
-                                               stridesName,
+      failed(isIntegerArrayAttrConfinedToRange(*this, strides, /*min=*/1,
+                                               /*max=*/1, stridesName,
                                                /*halfOpen=*/false)) ||
       failed(isSumOfIntegerArrayAttrConfinedToShape(
           *this, offsets,
@@ -3250,8 +3252,8 @@ LogicalResult ExtractStridedSliceOp::verify() {
       failed(isIntegerArrayAttrConfinedToShape(*this, sizes, shape, sizesName,
                                                /*halfOpen=*/false,
                                                /*min=*/1)) ||
-      failed(isIntegerArrayAttrConfinedToRange(*this, strides, 1, 1,
-                                               stridesName,
+      failed(isIntegerArrayAttrConfinedToRange(*this, strides, /*min=*/1,
+                                               /*max=*/1, stridesName,
                                                /*halfOpen=*/false)) ||
       failed(isSumOfIntegerArrayAttrConfinedToShape(*this, offsets, sizes,
                                                     shape, offName, sizesName,