Highlight key/value pair that triggered error symbol to display on the map

[ggeldenhuis]

When a node contains a tag that is not appropriate it will get highlighted with yellow box with a crossed through red circle in the box. It would be usefull to see which property caused this to happen by means of highlighting when selecting the node.

For example:
A node containing the tag:
highway=path
were highlighted as wrongly tagged for the node. It had 3 other tags so 4 in total. A visual highlight of the the "wrong" key/value pair in this case highway=path would be useful as one then does not need to evaluate each tag and can simply follow the visual clue to correct the problem.

[Don-vip]

Relevant ticket: #8512 to have a special mechanism with discardable keys.

I think the best solution is to define customizable colors for inappropriate and discardable tags.