Fix typos noticed by Benjamin Kramer.
Also make the checks stronger and test that we reject ranges that overlap
a previous wrapped range.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157749 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 45ee424..1f43ab6 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -3054,8 +3054,8 @@
    <li>The range should not represent the full or empty set. That is,
        <tt>a!=b</tt>. </li>
 </ul>
-<p> In addiion, the pairs must be in signed order of the lower bound and
-  they must be non contigous.</p>
+<p> In addition, the pairs must be in signed order of the lower bound and
+  they must be non-contiguous.</p>
 
 <p>Examples:</p>
 <div class="doc_code">