Fix hashtags not being picked up when full-width hash sign is used (#36103)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/mastodon/actions/compose.js

@@ -622,6 +622,7 @@ export function fetchComposeSuggestions(token) {
       fetchComposeSuggestionsEmojis(dispatch, getState, token);
       break;
     case '#':
+    case '＃':
       fetchComposeSuggestionsTags(dispatch, getState, token);
       break;
     default:
@@ -663,11 +664,11 @@ export function selectComposeSuggestion(position, token, suggestion, path) {
 
       dispatch(useEmoji(suggestion));
     } else if (suggestion.type === 'hashtag') {
-      completion    = `#${suggestion.name}`;
-      startPosition = position - 1;
+      completion    = suggestion.name.slice(token.length - 1);
+      startPosition = position + token.length;
     } else if (suggestion.type === 'account') {
-      completion    = getState().getIn(['accounts', suggestion.id, 'acct']);
-      startPosition = position;
+      completion    = `@${getState().getIn(['accounts', suggestion.id, 'acct'])}`;
+      startPosition = position - 1;
     }
 
     // We don't want to replace hashtags that vary only in case due to accessibility, but we need to fire off an event so that
@@ -727,7 +728,7 @@ function insertIntoTagHistory(recognizedTags, text) {
     // complicated because of new normalization rules, it's no longer just
     // a case sensitivity issue
     const names = recognizedTags.map(tag => {
-      const matches = text.match(new RegExp(`#${tag.name}`, 'i'));
+      const matches = text.match(new RegExp(`[#＃]${tag.name}`, 'i'));
 
       if (matches && matches.length > 0) {
         return matches[0].slice(1);

app/javascript/mastodon/components/autosuggest_input.jsx

@@ -61,7 +61,7 @@ export default class AutosuggestInput extends ImmutablePureComponent {
 
   static defaultProps = {
     autoFocus: true,
-    searchTokens: ['@', ':', '#'],
+    searchTokens: ['@', '＠', ':', '#', '＃'],
   };
 
   state = {

app/javascript/mastodon/components/autosuggest_textarea.jsx

@@ -25,7 +25,7 @@ const textAtCursorMatchesToken = (str, caretPosition) => {
     word = str.slice(left, right + caretPosition);
   }
 
-  if (!word || word.trim().length < 3 || ['@', ':', '#'].indexOf(word[0]) === -1) {
+  if (!word || word.trim().length < 3 || ['@', '＠', ':', '#', '＃'].indexOf(word[0]) === -1) {
     return [null, null];
   }