Proper spelling for wholesale METRO (should be Metro)

[dobridabar]

Please change spelling for wholesale METRO to Metro, because METRO is not an acronym.

After that, merge with Bulgarian "Metro", which was the only one that was spelled correctly.

Rationale (from: https://wiki.openstreetmap.org/wiki/Names): "Names are adapted to the local capitalisation rules; title case is generally preferred, but regional rules have preference over general rules."

It is true that Metro brands themselves in uppercase (METRO), but branding decision does not override OSM naming convention, which is to use title case (Metro). Too many companies brand themselves in uppercase, and writing their names in uppercase on OSM map would give them unfair advantage (*) over other companies which properly capitalize their brands.

(*) by taking more space on the map and being more visible

[Cj-Malone]

See #9337 / @Contrib1043