doc: correct some minor HTML errors found by tidy
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7439046
diff --git a/doc/debugging_with_gdb.html b/doc/debugging_with_gdb.html
index 4f1308a..b893f93 100644
--- a/doc/debugging_with_gdb.html
+++ b/doc/debugging_with_gdb.html
@@ -179,7 +179,7 @@
If for some reason GDB still can't find that directory or that script, you can load
it by hand by telling gdb (assuming you have the go sources in
<code>~/go/</code>):
-<p>
+</p>
<pre>
(gdb) <b>source ~/go/src/pkg/runtime/runtime-gdb.py</b>
