docs: add browser support information to limitations documentation

[getdave]

What

Adds browser support information to the limitations documentation page.

Why

Users need clear information about which browsers are supported by WordPress Playground to make informed decisions about compatibility and usage.

How

• Added new 'Browser support' section under 'In the browser'
• Documented support for major desktop and mobile browsers (Chrome, Firefox, Safari, Edge, and Chromium-based browsers)
• Included note about Opera Mini support uncertainty
• Maintained consistent documentation formatting and style

Testing

• Verify the new section displays correctly in the documentation
• Check that the formatting matches the existing documentation style
• Confirm the information is accurate and helpful for users

Screenshots

[Screenshots to be added]

[getdave]

@adamziel Here is the update as requested

[adamziel]

Thank you @getdave! This looks good to me. I'd just add a few bits:

• We don't support lockdown mode on iOS since since it disables WebAssembly support.
• We didn't confirm support on browsers not listed, e.g. Baidu browser etc. It should just work in everything based on Chromium but could theoretically break if a specific distro decided to disable some v8 features.

[fellyph]

@adamziel, it would be nice to set a test with Playwright to check those other browsers. I can send a Pull request with those tests.