webconfig: add link to pkg.go.dev/vuln, clean up links

Add a link to pkgsite for anyone who wants to browse the database.

Normalize the style of paragraphs containing links to "For X, see Y".
Remove inconsistent application of target="_blank".

For #56463

Change-Id: If20cd762aa338c83ebbae7306f07888e1fb9a083
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/446035
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Tim King <taking@google.com>

webconfig/index.html

@@ -23,21 +23,26 @@
       This is the Go vulnerability database. It is meant to be accessed by
       programs that want to find vulnerabilities associated with Go modules.
     </p>
+    <p>
+      To browse the database, see
+      <a href="https://pkg.go.dev/vuln/">pkg.go.dev/vuln</a>.
+    </p>
     <p>
       For the database schema, see
-      <a href="https://go.dev/security/vuln/database" target="_blank">go.dev/security/vuln/database</a>.
+      <a href="https://go.dev/security/vuln/database">go.dev/security/vuln/database</a>.
     </p>
     <p>
       For details on Go vulnerability management, see
-      <a href="https://go.dev/security/vuln" target="_blank">go.dev/security/vuln</a>.
+      <a href="https://go.dev/security/vuln">go.dev/security/vuln</a>.
     </p>
     <p>
-      See <a href="https://vuln.go.dev/privacy.html">vuln.go.dev/privacy</a> for privacy information about this service.
+      For privacy information about this service, see
+      <a href="https://vuln.go.dev/privacy.html">vuln.go.dev/privacy</a>.
     </p>
     <p>
-      See <a href="https://vuln.go.dev/copyright.html">vuln.go.dev/copyright</a>
-      for copyright and licensing information about the reports in this
-      database.
+      For copyright and licensing information about the reports in this
+      database, see
+      <a href="https://vuln.go.dev/copyright.html">vuln.go.dev/copyright</a>.
     </p>
   </body>
 </html>