Improve SSH key expiration warning emails

app/views/notify/ssh_key_expired_email.html.haml

 %p
   = _('Hi %{username}!') % { username: sanitize_name(@user.name) }
 %p
-  = _('Your SSH keys with the following fingerprints has expired:')
+  = _('Your SSH keys with the following fingerprints have expired. Expired SSH keys will not be usable in future versions of GitLab:')
 %table
   %tbody
     - @fingerprints.each do |fingerprint|

app/views/notify/ssh_key_expired_email.text.erb

 <%= _('Hi %{username}!') % { username: sanitize_name(@user.name) } %>
 
-<%= _('Your SSH keys with the following fingerprints has expired:') %>
+<%= _('Your SSH keys with the following fingerprints have expired. Expired SSH keys will not be usable in future versions of GitLab:') %>
 
 <% @fingerprints.each do |fingerprint| %>
   - <%= fingerprint %>

app/views/notify/ssh_key_expiring_soon.text.erb

 <%= _('Hi %{username}!') % { username: sanitize_name(@user.name) } %>
 
-<%= _('Your SSH keys with the following fingerprints are scheduled to expire soon:') %>
+<%= _('Your SSH keys with the following fingerprints are scheduled to expire soon. Expired SSH keys will not be usable in future versions of GitLab:') %>
 
 <% @fingerprints.each do |fingerprint| %>
   - <%= fingerprint %>

app/views/notify/ssh_key_expiring_soon_email.html.haml

 %p
   = _('Hi %{username}!') % { username: sanitize_name(@user.name) }
 %p
-  = _('Your SSH keys with the following fingerprints are scheduled to expire soon:')
+  = _('Your SSH keys with the following fingerprints are scheduled to expire soon. Expired SSH keys will not be usable in future versions of GitLab:')
 %table
   %tbody
     - @fingerprints.each do |fingerprint|

locale/gitlab.pot

@@ -37741,10 +37741,10 @@ msgstr ""
 msgid "Your SSH keys (%{count})"
 msgstr ""
 
-msgid "Your SSH keys with the following fingerprints are scheduled to expire soon:"
+msgid "Your SSH keys with the following fingerprints are scheduled to expire soon. Expired SSH keys will not be usable in future versions of GitLab:"
 msgstr ""
 
-msgid "Your SSH keys with the following fingerprints has expired:"
+msgid "Your SSH keys with the following fingerprints have expired. Expired SSH keys will not be usable in future versions of GitLab:"
 msgstr ""
 
 msgid "Your To-Do List"

spec/mailers/emails/profile_spec.rb

@@ -264,7 +264,7 @@ RSpec.describe Emails::Profile do
         include_examples 'valid use case'
 
         it_behaves_like 'has the correct subject', /Your SSH key has expired/
-        it_behaves_like 'has the correct body text', /Your SSH keys with the following fingerprints has expired/
+        it_behaves_like 'has the correct body text', /Your SSH keys with the following fingerprints have expired/
       end
 
       context 'when invalid' do