design/51082-godocfmt: add indented non-heading example

Change-Id: I532ae825ee7c48909ff53137669ffe80caf5fcf3
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/384434
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

design/51082-godocfmt.md

diff --git a/design/51082-godocfmt.md b/design/51082-godocfmt.md
index f6c9d9e..8a9c586 100644
--- a/design/51082-godocfmt.md
+++ b/design/51082-godocfmt.md
@@ -232,6 +232,8 @@
 	In the middle of a span of non-blank lines,
 	# this is not a heading either.
 
+	 # This is not a heading, because it is indented.
+
 The old heading rule will remain valid, which is acceptable since it mainly
 has false negatives, not false positives. This will keep existing doc comments
 rendering as they do today.