[web] Moving docs link to tootsuite/documentation (#1581)

related: https://github.com/tootsuite/mastodon/commit/1236529e39a7e2534fdd34686a749b5a386c109b and https://github.com/tootsuite/mastodon/commit/fc47c1d00e507f0bee2575c91822d68b72a22bac



Signed-off-by: lindwurm <lindwurm.q@gmail.com>

app/assets/javascripts/components/features/getting_started/index.jsx

@@ -43,7 +43,7 @@ const GettingStarted = ({ intl, me }) => {
 
       <div className='scrollable optionally-scrollable' style={{ display: 'flex', flexDirection: 'column' }}>
         <div className='static-content getting-started'>
-          <p><FormattedMessage id='getting_started.open_source_notice' defaultMessage='Mastodon is open source software. You can contribute or report issues on GitHub at {github}. {apps}.' values={{ github: <a href="https://github.com/tootsuite/mastodon" target="_blank">tootsuite/mastodon</a>, apps: <a href="https://github.com/tootsuite/mastodon/blob/master/docs/Using-Mastodon/Apps.md" target="_blank"><FormattedMessage id='getting_started.apps' defaultMessage='Various apps are available' /></a> }} /></p>
+          <p><FormattedMessage id='getting_started.open_source_notice' defaultMessage='Mastodon is open source software. You can contribute or report issues on GitHub at {github}. {apps}.' values={{ github: <a href="https://github.com/tootsuite/mastodon" target="_blank">tootsuite/mastodon</a>, apps: <a href="https://github.com/tootsuite/documentation/blob/master/Using-Mastodon/Apps.md" target="_blank"><FormattedMessage id='getting_started.apps' defaultMessage='Various apps are available' /></a> }} /></p>
         </div>
       </div>
     </Column>