document XSLT browser gotchas

[einkoro]

Write documentation on known XSLT browser gotchas. Common issues:

• gecko forgetting form data going back/forward in history or refresh [https://bugzilla.mozilla.org/show_bug.cgi?id=209292 209292]
• gecko does not auto fill saved data for forms [https://bugzilla.mozilla.org/show_bug.cgi?id=354706 354706]
• gecko doesn't implement the HTML-DOM for XHTML created as the result of an XSL Transformation [https://bugzilla.mozilla.org/show_bug.cgi?id=230214 230214]

[https://bugzilla.mozilla.org/buglist.cgi?quicksearch=xslt Gecko XSLT bug list] [https://bugs.webkit.org/buglist.cgi?bug_status=__open__&quicksearch=xslt Webkit XSLT bug list]

[einkoro]

Should we roll this into ticket:1?