In keyword filter, account for reblogs, HTML and whole-words (#7960)

* In keyword filter, account for reblogs, HTML and whole-words

* Match whole words in JS filter, too

* Fix typo

app/javascript/mastodon/selectors/index.js

@@ -43,7 +43,7 @@ const regexFromFilters = filters => {
     return null;
   }
 
-  return new RegExp(filters.map(filter => escapeRegExp(filter.get('phrase'))).join('|'), 'i');
+  return new RegExp(filters.map(filter => escapeRegExp(filter.get('phrase'))).map(expr => `\\b${expr}\\b`).join('|'), 'i');
 };
 
 export const makeGetStatus = () => {