Fix grammar.

llvm-svn: 16529
diff --git a/llvm/docs/ExtendingLLVM.html b/llvm/docs/ExtendingLLVM.html
index 8e2a904..1c2408a 100644
--- a/llvm/docs/ExtendingLLVM.html
+++ b/llvm/docs/ExtendingLLVM.html
@@ -108,8 +108,8 @@
 <li><tt>llvm/test/Regression/*</tt>: add your test cases to the test suite.</li>
 </ol>
 
-<p>If this intrinsic requires code generator support (ie, it cannot be lowered).
-You should also add support to the code generator in question.</p>
+<p>If this intrinsic requires code generator support (i.e., it cannot be
+lowered), you should also add support to the code generator in question.</p>
 
 </div>