[Feature request] Support multiple <meta name="theme-color">

[Unbinilium]

Feature request

Description

For better user experience, the browser should get color hex before the page loaded, but it seems vuepress-next does not currently supported the duplicated meta tags like this:

['meta', { name: 'theme-color', content: '#3eaf7c', media: '(prefers-color-scheme: light)' }],
['meta', { name: 'theme-color', content: '#22272e', media: '(prefers-color-scheme: dark)' }],

Related with vuepress/ecosystem#7 and #218

Proposed Solution

We are using following snippet to dedupe <meta> tag:

https://github.com/vuepress/vuepress-next/blob/33c9a2145eeaf53429f2ae784e393074d1a9edd5/packages/%40vuepress/shared/src/utils/resolveHeadIdentifier.ts#L11-L14

But I think that supporting multiple <meta name="theme-color"> tags should be another issue.

There's another problem.

Meta tags set in user config will be injected to client with useSiteData. So we also have to update the sitedata ref, or the tag will be reset once navigating to another page.

Originally posted by @meteorlxy in #218 (comment)

[meteorlxy]

According to the HTML Spec:

There must not be more than one meta element with its name attribute value set to an ASCII case-insensitive match for theme-color per document.

So this is a non-standard support of Safari 15.