Insert missing bracket in docs.

[ncv]

Summary

Body of unrolled loop was missing opening bracket.

[Meinersbur]

LGTM.

Thanks for catching.

[• post.kadirselcuk]

In D87329#2262102, @Meinersbur wrote:

LGTM.

Thanks for catching.

It's a request.

llvm/docs/TransformMetadata.rst

.. code-block:: c
     for (int i = 0; i < n; i+=1) // original loop
       Stmt(i);
 
 is transformed into (using an unroll factor of 4):
 
 .. code-block:: c
 
     int i = 0;
-    for (; i + 3 < n; i+=4) // unrolled loop
+    for (; i + 3 < n; i+=4) { // unrolled loop
       Stmt(i);
       Stmt(i+1);
       Stmt(i+2);
       Stmt(i+3);
     }
     for (; i < n; i+=1) // remainder loop
       Stmt(i);