GHC left some of the unused imports as `import X ()`

This is achieved by using `stack build --ghc-options=-ddump-minimal-imports`
and looking for the *.imports files.

This adds the "<" condition, it used as "in"

i.e. "<l₀l₁w₀w₁" reads as "if l₀ is a subset of l₁, then w₀ else w₁"

Useful for macro programming like, if Spotify is on the current
workspace, then go back to where I came from, otherwise jump to Spotify.
This can be achieved with the following (assuming Spotify is marked with
"s"):

"<H-g><s@.'@s"

"if spotify (s) is in the set of the windows on the current screen (@.), jump
back to where I came from (workspace '), otherwise goto the workspace
spotify is on (@s)."