email: review gmail submission documentation (tpo/tpa/team#42010)

I did the onboarding with gillian and things were not quite right. The
top NOTE was particularly confusing.

service/email.md

@@ -131,12 +131,11 @@ account configured and working, which the steps below assume is the case.
 
 ## Gmail configuration
 
-**NOTE**: This section explains how to reconfigure a gmail account
-that is _already_ configured to use a `torproject.org` address.  If
-you need to add a new address from scratch, the process will be a
-little different.
+Follow those steps to configure an existing Gmail account to send
+email through the Tor Project servers, to be able to send email with a
+`@torproject.org` identity.
 
- 1. log into your Gmail account in a web browser
+ 1. Log in to your Gmail account in a web browser
 
  2. Click on "Settings", that should be the big gear icon towards
     the top right of your window
@@ -147,10 +146,9 @@ little different.
  3. This will take you to a "Settings" page. Click on the "Accounts
     and Import" tab at the top of the page.
 
- 4. Under "Send mail as", find the address for
-    <yourname@torproject.org>, if the address is not there, click "Add
-    another email address" and first add an email address, then return
-    here
+ 4. Under "Send mail as", click "Add another email address" and add
+    the <yourname@torproject.org> address there. Keep the "treat as an
+    alias" box checked.
     
  5. Click the "edit info" link to the right of that account
 
@@ -160,17 +158,29 @@ little different.
     out like this:
 
     - Select "Send through torproject.org SMTP servers".
-    - Set "SMTP Server:" to "submission.torproject.org"
+    - Set "SMTP Server:" to `submission.torproject.org`, *not* `mx-dal-01.torproject.org`
     - Set "Port:" to 465.
-    - Set "Username:" to your username (_without_ "@torproject.org").
+    - Set "Username:" to your username (_without_ `@torproject.org`).
     - Set "Password:" to the email submission password that you configured.
-      - This password usually differs from the one used for logging in to
-        `db.torproject.org`. See [how to set the email password][].
-    - Keep "Secured connection using SSL (recommended)" selected
+      - This password is not the same as the one used for logging in
+        to `db.torproject.org`. See [how to set the email password][].
+    - Keep "Secured connection using SSL (recommended)" selected, the
+      other one "Secured connection using TLS"
+
+    Double-check everything, then click "Save Changes".  Gmail will
+    try authenticating to the SMTP server; if it's successful, then
+    the popup window will close and your account will be updated.
+
+ 7. A confirmation email will be sent to the <yourname@torproject.org>
+    which should forward back to your Gmail mailbox.
 
-Double-check everything, then click "Save Changes".  Gmail will try
-authenticating to the SMTP server; if it's successful, then the popup
-window will close and your account will be updated.
+ 8. Try sending a mail with your `@torproject.org` identity.
+
+    When you compose a new message, on the "From" line, there will now
+    be a drop-down menu, where you can pick your normal Gmail account
+    or the new `@torproject.org` account as your identity. 
+    
+    It might take a while to propagate.
 
 # How-to