DocCard category emoji fallback renders in text presentation

[dev-tsc]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Prerequisites

• I'm using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages.
• I have tried creating a repro with https://new.docusaurus.io.
• I have read the console error message carefully (if applicable).

Description

Since upgrading to Docusaurus v3.10, the 🗃 (Card File Box) emoji on generated-index pages renders as a monochrome text style glyph instead of a colorful emoji.

Root cause seems to be getFallbackEmojiIcon in DocCard with only the category icon affected. Looks unintentional. This was introduced in #11734

Reproducible demo

No response

Steps to reproduce

1. Sidebar with type : 'category' and a link with type: 'generated-index' (and no custom emoji provided in label)

Expected behavior

The 🗃️ emoji renders in color emoji presentation, consistent with pre v3.10 behavior and with the other DocCard emojis (📄️, 🔗) in the same function.

Actual behavior

Renders as monochrome

Your environment

• Public source code:
• Public site URL:
• Docusaurus version used: 3.10
• Environment name and version (e.g. Chrome 89, Node.js 16.4): Any browser, Node 24
• Operating system and version (e.g. Ubuntu 20.04.2 LTS): W11 25H2

Self-service

• I'd be willing to fix this bug myself.

[Josh-Cena]

Do you have a screenshot? It looks normal on my mac:

[dev-tsc]

Could also be OS-related I think. This is how it looks on Win 11 for me (in all browsers):

An here a comparison of v3.9 (left side) and v3.10 (right side) - taken from Github code view:
Notice how the emoji in L30 is already monochrome. Copy pasting the v3.10 emoji and dropping it into a Unicode converter gives this code point: `0x1F5C3`

Doing the same with the colorful one gives: 0x1F5C3,0xFE0F

According to this, U+FE0F specifies an "emoji-style (with color)". It is possible that Apple defaults to rendering emojis as colorful I guess.

[dev-tsc]

Minor correction: While what I found previously seems to be true, I overlooked one further point.

The default font-family (ifm-font-family-base) contains a specific emoji fallback and the override of my site does not. So a quick fix for me was to adjust the font-family of .theme-doc-card-icon.

Nevertheless this issue seems to be a regression that is easy to fix.

[markselby9]

Confirmed regression from #11734. Fix is to append U+FE0F to the '🗃' literal in packages/docusaurus-theme-classic/src/theme/DocCard/index.tsx:30 so it matches the sibling '📄️' convention two lines below. Happy to put up a small PR.