doc/cmd.html: close a tag.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/130560043

doc/cmd.html

@@ -65,7 +65,7 @@ details.
 <td><a href="//godoc.org/code.google.com/p/go.tools/cmd/cover/">cover</a></td>
 <td>&nbsp;&nbsp;&nbsp;&nbsp;</td>
 <td>Cover is a program for creating and analyzing the coverage profiles
-generated by <code>"go test -coverprofile"</code>.
+generated by <code>"go test -coverprofile"</code>.</td>
 </tr>
 
 <tr>