Minor instruction amendment for Deathroids

[tabreturn]

Folders ending in .app can appear as files on Mac, so I'm opting for more flexible wording here.
Also, some other text refinements.

[cdeletre]

technically folders ending with .app can contains an application (they are not a file). Here is an exemple:

cde@arcticfox Steam.app % tree -L 3
.
└── Contents
    ├── CodeResources
    ├── Frameworks
    │   ├── Breakpad.framework
    │   └── crashhandler.dylib
    ├── Info.plist
    ├── MacOS
    │   ├── public -> ../Resources/public
    │   ├── steam.sh -> steam_osx
    │   └── steam_osx
    ├── PkgInfo
    ├── Resources
    │   ├── Steam.icns
    │   └── public
    ├── _CodeSignature
    │   └── CodeResources
    └── embedded.provisionprofile

9 directories, 9 files