cmd refs: Updates per 1.x

[imhardikj]

All cmd refs that need to be updated per 1.x
Context: #1255 (comment)

Mainly descriptions, or everything

• repro - repro: improvements to targets arg and -R option #1632
• dag (rewrite description dag: rewrite explanation of what pipelines are #1500)
• commit (example for adding missing deps/outs cmd ref: improve run and commit / how to add outs/deps without re-running stage? #460/cmd ref: add commit example on adding missing dependency to existing pipeline #612) how-to: add stage outputs existing in the WS but missing from dvc.yaml #1840
• list + list: document usage for data export/archive #1521?
• target arg descriptions - cmd: update pending target arg descriptions #1574

Mainly examples

• run examples in other docs (also docs: simplify run examples, leaving bare min. usage #1700 and cmd ref: add a few lines about cache and no-commit in dvc run #186)
• status examples in all docs (including consistent indentation — may keep tabs) - cmd: status examples #1952
• pending plots updates cmd: update metrics/plots docs per recent changes #1175 cmd: pending plots changes by 1.0 release #1414
• fetch (examples) - cmd: some example updates as per 1.x #1903
• pull (examples) - cmd: some example updates as per 1.x #1903
• get (examples) - cmd: some example updates as per 1.x #1903
• params diff (examples docs: List instances of stage file concepts, dvc run/checkout/repro for example review and update to 1.0 #1743) -
• version - cmd: update version ref. #1635
• root (new example cmd ref: review root ref to be aligned with other commands #404)

[jorgeorpinel]

@imhardikj the version updates were merged some days ago. Any more progress on the above list? We need to pick up the pace here or not much will be done during GSoD, thanks.

[jorgeorpinel]

Closed by #2075.