[docs] Fix typo in docs/CodeGenerator.rst.

llvm-svn: 263479
diff --git a/llvm/docs/CodeGenerator.rst b/llvm/docs/CodeGenerator.rst
index f3b949c..f509594 100644
--- a/llvm/docs/CodeGenerator.rst
+++ b/llvm/docs/CodeGenerator.rst
@@ -45,7 +45,7 @@
    ``include/llvm/CodeGen/``. At this level, concepts like "constant pool
    entries" and "jump tables" are explicitly exposed.
 
-3. Classes and algorithms used to represent code as the object file level, the
+3. Classes and algorithms used to represent code at the object file level, the
    `MC Layer`_.  These classes represent assembly level constructs like labels,
    sections, and instructions.  At this level, concepts like "constant pool
    entries" and "jump tables" don't exist.