Expose enableEmoji as a site variable

[rootwork]

From #7170:

Hugo themes determine what text gets emojified for us and what doesn't. Hugo already helps to emojify content if enableEmoji is set to true. In order to give the greatest flexibility and control enableEmoji should be exposed as a site variables (i.e. .Site.EnableEmoji).

This would allow themes to conditionally run text (like titles) through emojify if enableEmoji is set; currently there's no way to do this and respect the site config.

(Since the Hugo repo aggressively closes proposals that have no activity on them, the only way I could add my "+1" to the #7170 proposal was to create a new issue.)

[bep]

No, we're not doing this. I have written about this before, but we're very restrictive about making the site configuration part of the API, as it usually restricts future changes in some unknown way.

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.