Remove an obsolete error from the spec and an obsolete command-line flag

pkg/analysis_server/tool/spec/spec_input.html

Index: pkg/analysis_server/tool/spec/spec_input.html
diff --git a/pkg/analysis_server/tool/spec/spec_input.html b/pkg/analysis_server/tool/spec/spec_input.html
index 8d288218f40031eb52ebf122d8d43b4371a5a742..05f81983adf6dfffbb6393211a92161dc5fbab99 100644
--- a/pkg/analysis_server/tool/spec/spec_input.html
+++ b/pkg/analysis_server/tool/spec/spec_input.html
@@ -175,13 +175,11 @@
       </dd>
     </dl>
     <dl>
-      <dt>--no-index</dt>
+      <dt class="deprecated">--no-index</dt>
       <dd>
-      Disable the server from generating an index. If this flag is passed and an
-      API is used that requires an index, then an error, <tt>NO_INDEX_GENERATED</tt>,
-      will be thrown. The set of API calls that require an index include:
-      refactoring calls, code completions and searching.
-      <!-- TODO(jwren/scheglov): make sure that this list of APIs that is complete. -->
+        <p><b>Deprecated:</b> clients should no longer pass this option in</p>
+        This flag used to disable the server from generating an index, but now
+        it has no effect.
       </dd>
     </dl>
     <dl>
@@ -3900,13 +3898,6 @@
             </p>
           </value>
           <value>
-            <code>NO_INDEX_GENERATED</code>
-            <p>
-              The "--no-index" flag was passed when the analysis server created,
-              but this API call requires an index to have been generated.
-            </p>
-          </value>
-          <value>
             <code>ORGANIZE_DIRECTIVES_ERROR</code>
             <p>
               An "edit.organizeDirectives" request specified a Dart file that