_content/doc/devel: fix article formatting

Previously, the release notes for Go 1.20.9 and 1.21.1 note "one
security fixes" instead of "a security fix." We could change the
content of internal/history/release.go but feels better to do the
right thing even if people do this same thing again.

Change-Id: I6817e0023f45b09f7a26dc58753001484218cf99
Reviewed-on: https://go-review.googlesource.com/c/website/+/569375
LUCI-TryBot-Result: Go LUCI <[email protected]>
Auto-Submit: Kevin Burke <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>

Author: kevinburke

_content/doc/devel/release.html

@@ -46,7 +46,7 @@ <h2 id="go{{.Version}}">go{{.Version}} (released {{.Date}})</h2>
 			{{with .Security}}
 				{{.Quantifier}}
 				security
-				{{if eq .Quantifier "a"}}fix{{else}}fixes{{end -}}
+				{{if (or (eq .Quantifier "a") (eq .Quantifier "one"))}}fix{{else}}fixes{{end -}}
 				{{with .ComponentsAndPackages}} to {{.}}{{end -}}
 			{{end}}
 			{{- if and .Security .Bug}}, as well as{{end -}}