fix(button): render with console markup

[TomJGooding]

Fixes #4328.

I've added a new snapshot test - here's a screenshot showing the difference after/before this change:

Please review the following checklist.

• Docstrings on all new or modified functions / classes
• Updated documentation
• Updated CHANGELOG.md (where appropriate)

[TomJGooding]

Something I noticed is that the shade is red is different comparing against v0.40.0, but it looks like there must have been other changes as Static and Label show the same difference...

Textual v0.40.0

Now

from textual.app import App, ComposeResult
from textual.widgets import Button, Label, Static


class ButtonsWithMarkupApp(App):
    def compose(self) -> ComposeResult:
        yield Button("[italic red]Focused[/] Button")
        yield Button("[italic red]Blurred[/] Button")
        yield Button("[italic red]Disabled[/] Button", disabled=True)

        yield Static("[italic red]Test[/] Static")
        yield Label("[italic red]Test[/] Label")


if __name__ == "__main__":
    app = ButtonsWithMarkupApp()
    app.run()

[willmcgugan]

Something I noticed is that the shade is red is different comparing against v0.40.0, but it looks like there must have been other changes as Static and Label show the same difference...

We changed the default dark ansi theme from DIMMED_MONOKAI to MONOKAI. Personally I prefer the dimmed version, but I was outnumbered. 🤷

[rodrigogiraoserrao]

Looks good to me.