internal/frontend: remove unused messageTemplate

fetch.tmpl doesn't have a `{template "message"}` in it, so
`errorPage.messageTemplate` is not used and can be omitted.

Change-Id: I47e60c81ba97fdb952bd0a69b76bb651b8861cf3
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/255098
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/internal/frontend/details.go b/internal/frontend/details.go
index 8e661a4..d49122f 100644
--- a/internal/frontend/details.go
+++ b/internal/frontend/details.go
@@ -418,12 +418,7 @@
 		status: http.StatusNotFound,
 		epage: &errorPage{
 			templateName: "fetch.tmpl",
-			messageTemplate: template.MakeTrustedTemplate(`
-				<h3 class="NotFound-message">Oops! {{.}} does not exist.</h3>
-				<p class="NotFound-message js-notFoundMessage">
-					Check that you entered it correctly, or request to fetch it.
-				</p>`),
-			MessageData: path,
+			MessageData:  path,
 		},
 	}
 }