Test format on save

[jrieken]

Test for #12449

• any os @bgashler1
• any os @kieferrm

Complexity 2

We added support to format a document on save. Please test that

• there is a setting editor.formatOnSave and that the setting is documented and a good fit
• format on save won't work when auto save is on
• format on save works with all the other save options (focus lost etc)
• format on save produces the same result as the format action from the context-menu would

[chrmarti]

@jrieken I'm assuming this also covers #239.

[jrieken]

@chrmarti I have added #12640 for that

[kieferrm]

#12827 is the only "issue" I found with this feature.

[bgashler1]

@jrieken Small thing, I would just put a comma before the conjunction "and" so it's not a run-on sentence.