[MLIR][SCF][NFC] Fix typo in documentation of scf.while

[jurahul]

Summary

• scf.yield in the "after" region supplies new arguments to the "before" region.

mlir/include/mlir/Dialect/SCF/SCFOps.td

let description = [{
     that accepts as its first operand an `i1` value indicating whether to
     proceed to the "after" region (value is `true`) or not. The two regions
     communicate by means of region arguments. Initially, the "before" region
     accepts as arguments the operands of the `scf.while` operation and uses them
     to evaluate the condition. It forwards the trailing, non-condition operands
     of the `scf.condition` terminator either to the "after" region if the
     control flow is transferred there or to results of the `scf.while` operation
     otherwise. The "after" region takes as arguments the values produced by the
-    "before" region and uses `scf.yield` to supply new arguments for the "after"
-    region, into which it transfers the control flow unconditionally.
+    "before" region and uses `scf.yield` to supply new arguments for the
+    "before" region, into which it transfers the control flow unconditionally.
 
     A simple "while" loop can be represented as follows.
 
     ```mlir
     %res = scf.while (%arg1 = %init1) : (f32) -> f32 {
       /* "Before" region.
        * In a "while" loop, this region computes the condition. */
       %condition = call @evaluate_condition(%arg1) : (f32) -> i1