docs: more Markdown touch-ups

- replace the "none" code-hint with "console"
- some changes in the "experimental" instructions
- reformat some notes
- reformat / re-indent JSON output to use 2 spaces (for consistency)
- split JSON outputs to separate code-block so that it can be highlighted

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 4d948e468b)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

docs/reference/commandline/run.md

@@ -433,7 +433,7 @@ variables. (Unlike environment variables, labels are not visible to processes
 running inside a container.) The following example illustrates a label-file
 format:
 
-```none
+```console
 com.example.label1="a label"
 
 # this is a comment