Don't add obviously unnecessary steps

[mgirlich]

It would be a bit nicer to not add a step when it is obviously not necessary.

empty dots -> nothing to do

• arrange()
• filter(): in Don't add obviously unnecessary steps #255
• mutate(): in Group transmute #247
• relocate(): in Join without merge #240
• rename(), rename_with(): since Add step_setnames() #241

can easily analyse if anything changes:

• relocate(): in Join without merge #240
• rename(), rename_with(): since Add step_setnames() #241
• select(): in Don't add obviously unnecessary steps #255
• group_by(), ungroup(): in Don't add obviously unnecessary steps #255
• slice()

Not obvious way when to skip steps

• count(), tally(), add_count(), add_tally(): number of rows
• distinct(): use all variables
• summarise()
• transmute()
• slice_*()