Change icons in web UI (#27385)

Co-authored-by: Renaud Chaput <renchap@gmail.com>

app/javascript/mastodon/components/status_content.jsx

@@ -9,6 +9,8 @@ import { Link, withRouter } from 'react-router-dom';
 import ImmutablePropTypes from 'react-immutable-proptypes';
 import { connect } from 'react-redux';
 
+import { ReactComponent as ChevronRightIcon } from '@material-symbols/svg-600/outlined/chevron_right.svg';
+
 import { Icon }  from 'mastodon/components/icon';
 import PollContainer from 'mastodon/containers/poll_container';
 import { autoPlayGif, languages as preloadedLanguages } from 'mastodon/initial_state';
@@ -257,7 +259,7 @@ class StatusContent extends PureComponent {
 
     const readMoreButton = renderReadMore && (
       <button className='status__content__read-more-button' onClick={this.props.onClick} key='read-more'>
-        <FormattedMessage id='status.read_more' defaultMessage='Read more' /><Icon id='angle-right' fixedWidth />
+        <FormattedMessage id='status.read_more' defaultMessage='Read more' /><Icon id='angle-right' icon={ChevronRightIcon} />
       </button>
     );