Changing a code block to text because Sphinx does not like it on the builder (http://lab.llvm.org:8011/builders/llvm-sphinx-docs/builds/12517/steps/docs-llvm-html/logs/stdio)

llvm-svn: 280247
diff --git a/llvm/docs/Coroutines.rst b/llvm/docs/Coroutines.rst
index 5a95558..0e7cde7 100644
--- a/llvm/docs/Coroutines.rst
+++ b/llvm/docs/Coroutines.rst
@@ -812,7 +812,7 @@
 Example (custom deallocation function):
 """""""""""""""""""""""""""""""""""""""
 
-.. code-block:: llvm
+.. code-block:: text
 
   cleanup:
     %mem = call i8* @llvm.coro.free(token %id, i8* %frame)
@@ -827,7 +827,7 @@
 Example (standard deallocation functions):
 """"""""""""""""""""""""""""""""""""""""""
 
-.. code-block:: llvm
+.. code-block:: text
 
   cleanup:
     %mem = call i8* @llvm.coro.free(token %id, i8* %frame)