Clarify example snippets a bit.

llvm-svn: 143224
diff --git a/llvm/docs/ProgrammersManual.html b/llvm/docs/ProgrammersManual.html
index 4460224..2cdcd27 100644
--- a/llvm/docs/ProgrammersManual.html
+++ b/llvm/docs/ProgrammersManual.html
@@ -998,7 +998,7 @@
 <pre>
 for ( ... ) {
    std::vector&lt;foo&gt; V;
-   use V;
+   // make use of V.
 }
 </pre>
 </div>
@@ -1009,7 +1009,7 @@
 <pre>
 std::vector&lt;foo&gt; V;
 for ( ... ) {
-   use V;
+   // make use of V.
    V.clear();
 }
 </pre>