* fixup: remove excess whitespace
* du: various tweaks
- improve main description (include what "du" stands for)
- simplify globbing example
- unify nomenclature of folder/directory
- minor tweaks to existing descriptions
* du: a bunch of further rewordings
these changes aim to improve both clarity but also the sequence of commands to make it easier to build a mental model of how the tool works.
* osx/du: sync w/ changes in the linux folder
* linux/du: sync w/ changes in the osx folder
* remove slighly redundant «recursively» to make description simpler