Mark data for certain Android Browser versions sourced from MDN as "support unknown" instead of "unsupported"

[KarolS]

The compatibility matrix on MDN often lists the first supported Android WebView (Android Browser) version as 4.4, even for such trivial things like <br>: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/br

This leads to caniuse claiming AB 4.3 does not support those features: https://caniuse.com/mdn-html_elements_br

Note that is this example, minimum desktop Safari version was listed as 4 on MDN, yet the lower versions were not marked on caniuse as unsupported. This is a minor inconsistency.