Update documentation on precision for data sizes

[erikjv]

While fixing owncloud/client#11024 , we changed the way data sizes are displayed. We do what macOS 10.8 and above do: 0 fraction digits for bytes and KB; 1 fraction digits for MB; 2 for GB and above.

[michaelstingl]

But it's still JEDEC based?

• https://en.wikipedia.org/wiki/JEDEC_memory_standards
  (same as oC10 + classic web + Android app)

Related:

• https://github.com/owncloud/enterprise/issues/5808

[mmattel]

@erikjv @michaelstingl What is the change you want to show in docs and which releases are affected? Please do not use issues here as dump and search.

[michaelstingl]

which releases are affected

6.x+, I added the Milestone ✅

[michaelstingl]

I'd add a reference to the JEDEC here:

• https://github.com/owncloud/docs-client-desktop/blob/8f71cf2b98475d0f35a2db90a8896cd46c325619/modules/ROOT/pages/faq.adoc#how-to-interpret-quotas
  (all versions)