RFC: change Docusaurus admonition warning color from red to yellow

[slorber]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Motivation

This is what Docusaurus displays if you use :::warning

I believe it should be:

---

Note: Infima already uses alert--warning class for this yellow color.

Maybe this is a historical typo?

Most likely coming from our remark-admonition dependency:

https://github.com/elviswolcott/remark-admonitions/blob/master/lib/index.js#L31

  warning: {
    ifmClass: "danger",
    keyword: "warning",
    emoji: "🔥", //'🔥'
  },
  caution: {
    ifmClass: "warning",
    keyword: "caution",
    emoji: "⚠️", // '⚠️'
  }

---

All other doc tools use yellow for warnings:

v1.vuepress.vuejs.org/guide/markdown.html#custom-containers

nextra.vercel.app/themes/docs/callout

vitepress.vuejs.org/guide/markdown.html#custom-containers

docs.gitbook.com/editing-content/rich-content/with-command-palette#hints-and-callouts

---

The migration strategy remains to be defined: how do we avoid user site admonitions to move from red to yellow without them being aware of this change?

Important note: we don't even document :::warning, it is a historical alias/shortcut for :::caution which is how to use the yellow admonition color today.

Are there a lot of third-party sites using :::warning today?

:::caution is less natural to me: should we deprecate it in favor of a new first-class (not an alias) :::warning admonition key?

(although in practice there's not a clear difference of an alias vs a first class admonition key)

Related to #7556

Self-service

• I'd be willing to do some initial work on this proposal myself.