Deprecated functions get their own sections.

A small handful of functions got a 'Deprecated:' prefix instead in
documentation.

Change-Id: Ic151fb7d797514add66bc6465b6851b666a471bc
Reviewed-on: https://boringssl-review.googlesource.com/5825
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/util/doc.go b/util/doc.go
index 0ab6f89..8bbcd4c 100644
--- a/util/doc.go
+++ b/util/doc.go
@@ -451,7 +451,7 @@
 	if end > 0 {
 		end += start
 		w := strings.ToLower(string(s[start:end]))
-		if w == "a" || w == "an" || w == "deprecated:" {
+		if w == "a" || w == "an" {
 			start = end + 1
 			goto again
 		}