When setup issues raise opcache configuration errors, point at the opcache configuration page

Summary:
Fixes T11746. The opcache docs are on a different page, so point there if we're raising opcache issues.

(It's possible for a setup issue to say "configure X, or configure Y", where X is opcache and Y is non-opcache, so we may want to render both links.)

Test Plan: {F1867109}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11746

Differential Revision: https://secure.phabricator.com/D16685

src/applications/config/view/PhabricatorSetupIssueView.php

@@ -404,12 +404,24 @@ final class PhabricatorSetupIssueView extends AphrontView {
         implode("\n", $more_loc));
     }
 
+    $show_standard = false;
+    $show_opcache = false;
+
+    foreach ($configs as $key) {
+      if (preg_match('/^opcache\./', $key)) {
+        $show_opcache = true;
+      } else {
+        $show_standard = true;
+      }
+    }
+
+    if ($show_standard) {
       $info[] = phutil_tag(
         'p',
         array(),
         pht(
-        'You can find more information about PHP configuration values in the '.
+          'You can find more information about PHP configuration values '.
-        '%s.',
+          'in the %s.',
           phutil_tag(
             'a',
             array(
@@ -417,6 +429,23 @@ final class PhabricatorSetupIssueView extends AphrontView {
               'target' => '_blank',
             ),
             pht('PHP Documentation'))));
+    }
+
+    if ($show_opcache) {
+      $info[] = phutil_tag(
+        'p',
+        array(),
+        pht(
+          'You can find more information about configuring OPCache in '.
+          'the %s.',
+          phutil_tag(
+            'a',
+            array(
+              'href' => 'http://php.net/manual/opcache.configuration.php',
+              'target' => '_blank',
+            ),
+            pht('PHP OPCache Documentation'))));
+    }
 
     $info[] = phutil_tag(
       'p',