feat: Emoji reaction shorthand (#12650)

* Add "+:emoji:" reaction shorthand to comment form

Typing a comment that consists solely of a leading "+" followed by a
single emoji now adds that emoji as a reaction to the comment above,
instead of posting a new reply — mirroring the Slack shorthand.

https://claude.ai/code/session_01RSiUiEFLBaRF6YBfPNPiX6

* Move parseReactionShorthand into editor/lib/emoji

https://claude.ai/code/session_01RSiUiEFLBaRF6YBfPNPiX6

* Open emoji menu when colon is preceded by a plus

The suggestion menu's trigger boundary excluded "+", so typing "+:" never
opened the emoji menu — preventing the "+:emoji:" reaction shorthand from
being typed. Add a configurable `precededBy` option to the Suggestion
extension and set it to "+" for the emoji menu.

https://claude.ai/code/session_01RSiUiEFLBaRF6YBfPNPiX6

* Always allow "+" before suggestion trigger

Simplify by adding "+" to the trigger boundary for all suggestion menus
rather than making it a per-menu option. This lets the "+:emoji:" reaction
shorthand open the emoji menu.

https://claude.ai/code/session_01RSiUiEFLBaRF6YBfPNPiX6

---------

Co-authored-by: Claude <noreply@anthropic.com>

app/editor/extensions/Suggestion.ts

@@ -46,7 +46,7 @@ export default class Suggestion<
         : `(?:${triggers.map(escapeRegExp).join("|")})`;
 
     this.openRegex = new RegExp(
-      `(?:^|\\s|\\(|[\\p{Script=Han}\\p{Script=Hiragana}\\p{Script=Katakana}\\p{Script=Hangul}])${triggerPattern}(${`[\\p{L}/\\p{M}\\d${
+      `(?:^|\\s|\\(|\\+|[\\p{Script=Han}\\p{Script=Hiragana}\\p{Script=Katakana}\\p{Script=Hangul}])${triggerPattern}(${`[\\p{L}/\\p{M}\\d${
         this.options.allowSpaces ? "\\s{1}" : ""
       }\\.\\-–_]+`})${this.options.requireSearchTerm ? "" : "?"}$`,
       "u"

app/scenes/Document/components/Comments/CommentForm.tsx

@@ -8,6 +8,7 @@ import * as React from "react";
 import { useTranslation } from "react-i18next";
 import { toast } from "sonner";
 import { useTheme } from "styled-components";
+import { parseReactionShorthand } from "@shared/editor/lib/emoji";
 import type { ProsemirrorData } from "@shared/types";
 import { getEventFiles } from "@shared/utils/files";
 import { AttachmentValidation, CommentValidation } from "@shared/validations";
@@ -157,6 +158,30 @@ function CommentForm({
       return;
     }
 
+    // "+:emoji:" shorthand: react to the comment above instead of replying.
+    if (thread && !thread.isNew) {
+      const emoji = parseReactionShorthand(draft);
+      if (emoji) {
+        const target = comments
+          .inThread(thread.id)
+          .filter((comment) => !comment.isNew)
+          .pop();
+
+        if (target) {
+          onSaveDraft(undefined);
+          setForceRender((s) => ++s);
+          void target.addReaction({ emoji, user });
+          onSubmit?.();
+
+          // re-focus the comment editor
+          setTimeout(() => {
+            editorRef.current?.focusAtStart();
+          }, 0);
+          return;
+        }
+      }
+    }
+
     const commentDraft = draft;
     onSaveDraft(undefined);
     setForceRender((s) => ++s);