fix unreal.yaml

This PR fixes two issues.

1. Unreal.det and Unreal.est have incorrect sha1 sums, so unreal-de-data and unreal-es-data aren't buildable. For example:

identifying /usr/share/games/unreal/System/Unreal.det
WARNING:game_data_packager.build:found possible "system/unreal.det" but it is not one of the expected versions:
    file:   /usr/share/games/unreal/System/Unreal.det
    size:   198 bytes
    md5:    acfd984afd5e1feac325762550281e7b
    sha1:   70fe8331f9096f2246032394ccb6310cb45a504c
    sha256: e16546618621b00cf3dbf8be138907376cc78d0c9611eca9912216abca758f55
expected one of:
  System/Unreal.det?cd:
    size:   91 bytes
    md5:    ce4218544d06fdf63b1e1765ead034aa
    sha1:   None
    sha256: None
  System/Unreal.det?226b:
    size:   84 bytes
    md5:    2d5a47b1a8d4487af054d7e7ce047fbb
    sha1:   92bea870ce393e385a461b8b16024fae4b37a5ce
    sha256: f4fea7dce54f02651fb38a610ed7d303efc9cb2e266872bf1f31898c2ffe9dbd
  System/Unreal.det:
    size:   198 bytes
    md5:    acfd984afd5e1feac325762550281e7b
    sha1:   116ac8bedfa3aa0cb3cd5b49065c03d7196e6156
    sha256: e16546618621b00cf3dbf8be138907376cc78d0c9611eca9912216abca758f55

2. unreal-es-data, unreal-fr-data and unreal-it-data all require docs for package building. This PR marks these docs.