Various improvements and fixes

[NikitaIvanovV]

Hi! I'm the one who asked for dmenu support, thanks for adding it! :)

Some fixes and improvements:

• ccbd3e2 The original solution checks if a binary file exists in /usr/bin directory, but it's not a reliable way to check if a program is installed because one can have their binary located in any other PATH directory
• 1be1094 To make dmenu menu look like a list
• 7b39af7 This unnecessary line creates an empty item in dmenu
• 650ca05 /usr/bin/env bash is a preferred shebang for bash scripts because it allows bash to be located in places other than /bin
• 51492c8 /usr/bin is used for binaries installed by system package manager and should not by touched by users, thus /usr/local/bin is a preferred location for manually installed binaries

[ElnuDev]

Thanks so much for the PR! I'm pretty new to bash scripting, this was really helpful. The unnecessary \n was actually creating an empty item in rofi as well, somehow missed that. Really appreciate it!