[Docs] Use code-block:: text for part of the callbr documentation to attempt to make the bot happy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353567 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index ea941eb..044f352 100644
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -6912,7 +6912,7 @@
 Example:
 """"""""
 
-.. code-block:: llvm
+.. code-block:: text
 
       callbr void asm "", "r,x"(i32 %x, i8 *blockaddress(@foo, %fail))
                   to label %normal or jump [label %fail]