gracefully handle internal exceptions during request

pkg/analysis_server/doc/api.html

Index: pkg/analysis_server/doc/api.html
diff --git a/pkg/analysis_server/doc/api.html b/pkg/analysis_server/doc/api.html
index 95fff63b93a8b5be3d5f079bfdb335737474676e..f46adff8733d161231a9f191e883d8509e7ddf88 100644
--- a/pkg/analysis_server/doc/api.html
+++ b/pkg/analysis_server/doc/api.html
@@ -2627,6 +2627,12 @@ dt.typeDefinition {
               the analysis server can only speak to one client at a
               time so this error will never occur.
             </p>
+          </dd><dt class="value">SERVER_ERROR</dt><dd>
+            
+            <p>
+              An internal error occurred in the analysis server.
+              Also see the server.error notification.
+            </p>
           </dd><dt class="value">UNANALYZED_PRIORITY_FILES</dt><dd>
             
             <p>