pass custom title and icon to github alert

[hichemfantar]

Is your feature request related to a problem? Please describe. A clear and
concise description of what the problem is. Ex. I'm always frustrated when [...]

I'd love to use the existing alert components with my own titles

Describe the solution you'd like A clear and concise description of what you
want to happen.

pass a simple title prop

Describe alternatives you've considered A clear and concise description of
any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature
request here.

docusaurs allows this but for now, a simple title and icon props are enough and simple to implement

[dimaMachina]

#4088 (comment)