doc: fix escaping in weekly.html

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5306070

doc/devel/weekly.html

@@ -51,7 +51,7 @@ signatures updated.
 * gotest: explicit -help flag, use $GCFLAGS like make does.
 * govet: check canonical dynamic method signatures.
 * html: improved parsing (thanks Andrew Balholm),
-	parse <select> tags, parse and render comment nodes,
+	parse &lt;select&gt; tags, parse and render comment nodes,
 	remove the Tokenizer.ReturnComments option.
 * http: Transport: with TLS InsecureSkipVerify, skip hostname check.
 * misc/vim: add highlighting for delete (thanks Dave Cheney).