Better troubleshoot guide to kill existing running instance

Summary: Combine the two used commands as will make things easier for our users.

Reviewed By: passy

Differential Revision: D48266474

fbshipit-source-id: 1ee5c568ff001dc5ba3f11e21b09a2a6ab430ac7

desktop/flipper-server-client/src/FlipperServerClient.tsx

@@ -50,7 +50,7 @@ export function createFlipperServerWithSocket(
           new Error(
             `Failed to connect to the server in a timely manner.
              It may be unresponsive. Run the following from the terminal 
-             'sudo lsof -i :52342' and kill the listed process, if any.`,
+             'sudo kill $(lsof -t -i :52342)' as to kill any existing running instance, if any.`,
           ),
         );
       }, CONNECTION_TIMEOUT);

desktop/flipper-ui-core/src/chrome/SettingsSheet.tsx

@@ -432,11 +432,7 @@ class SettingsSheet extends Component<Props, State> {
                         process listening at port <b>52342</b>. See below:
                       </span>
                       <br />
-                      <code>
+                      <code>sudo kill $(lsof -t -i :52342)</code>
-                        sudo lsof -i :52342
-                        <br />
-                        sudo kill &lt;PID&gt;
-                      </code>
                     </>
                   ) : (
                     <></>

desktop/flipper-ui-core/src/dispatcher/flipperServer.tsx

@@ -210,7 +210,7 @@ function handeEADDRINUSE(errorMessage: string) {
         <br />
         <br />
         Please try to kill the offending process by running{' '}
-        <code>kill $(lsof -ti:PORTNUMBER)</code> and restart flipper.
+        <code>sudo kill $(lsof -ti:PORTNUMBER)</code> and restart flipper.
         <br />
         <br />
         {errorMessage}