Suspect differences between IE and Edge support

https://github.com/mdn/browser-compat-data/pull/23791 was a case where there was an IE version, but Edge was set to mirror, resulting in Edge 79. This is probably correct in some case, but there are probably more errors of this sort.

comm -23 <(npm run traverse -- -b edge -f mirror | sort) <(npm run traverse -- -b ie -f false -f null | sort) produces this list for review:

• api.BeforeUnloadEvent (https://github.com/mdn/browser-compat-data/pull/23797)
• api.BeforeUnloadEvent.returnValue (https://github.com/mdn/browser-compat-data/pull/23797)
• api.Document.releaseCapture
• api.IDBObjectStore.autoIncrement
• api.IDBObjectStore.openKeyCursor
• api.Navigator.taintEnabled (tested; data is correct)
• api.Window.beforeunload_event.event_returnvalue_activation
• api.Window.showModalDialog
• css.properties.overflow-x.auto (https://github.com/mdn/browser-compat-data/pull/23798)
• css.properties.overflow-y.auto (https://github.com/mdn/browser-compat-data/pull/23798)
• css.properties.overflow.auto (https://github.com/mdn/browser-compat-data/pull/23798)
• css.properties.text-combine-upright.digits
• css.selectors.placeholder-shown
• html.elements.iframe.sandbox.allow-same-origin
• html.elements.link.rel.alternate_stylesheet
• html.elements.link.rel.prerender
• html.elements.rb
• html.elements.rp (https://github.com/mdn/browser-compat-data/pull/23791)
• html.elements.rt (https://github.com/mdn/browser-compat-data/pull/23791)
• html.elements.source.height
• html.elements.source.width
• html.elements.wbr (https://github.com/mdn/browser-compat-data/pull/23804)
• svg.elements.circle.fill
• svg.elements.ellipse.fill
• svg.elements.path.fill
• svg.elements.pattern.href
• svg.elements.polygon.fill
• svg.elements.polyline.fill
• svg.elements.rect.fill
• svg.elements.text.fill
• svg.elements.textPath.fill
• svg.elements.tspan.fill

Start with the npm run traverse command in the issue and compare its IE and Edge output. Review the unchecked entries, including the listed API, CSS, HTML, and SVG paths, against the project’s compatibility data. Done means each discrepancy has been verified and the relevant data is corrected or confirmed.