_content/doc/go1.18: go fix requires go.mod go 1.18 for go:build change

Fixes golang/go#51873

Change-Id: Ied51c36a30cd18ff4a84d164e62df2690931d94f
Reviewed-on: https://go-review.googlesource.com/c/website/+/396879
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Trust: Ian Lance Taylor <iant@google.com>
diff --git a/_content/doc/go1.18.html b/_content/doc/go1.18.html
index 00a5058..c4281e2 100644
--- a/_content/doc/go1.18.html
+++ b/_content/doc/go1.18.html
@@ -473,7 +473,7 @@
 all supported versions of Go now understand <code>//go:build</code> lines.
 In Go 1.18, <code>go</code> <code>fix</code> now removes the now-obsolete
 <code>//</code> <code>+build</code> lines in modules declaring
-<code>go</code> <code>1.17</code> or later in their <code>go.mod</code> files.
+<code>go</code> <code>1.18</code> or later in their <code>go.mod</code> files.
 </p>
 
 <p>