cmd/cue: convert examples to 'cue vet -c'

https://cuelang.org/issue/2120 discusses at length the problems
associated with the tri-state of cue vet. https://cuelang.org/issue/3733
captures the higher level plan to do a "v2" of vet.

In the interim, we are trying to nudge people towards using -c
explicitly, either plain '-c' when they want concrete validation, or
'-c=false' when they want incomplete.

The help text for cue vet should also therefore nudge in the right
direction.

This CL fixes that; both examples expect concrete validation against
data files, hence use '-c'.

Signed-off-by: Paul Jolly <[email protected]>
Change-Id: Ie7cae87213987aa4f03278c2df00f4d03c51d5ef
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1213356
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

Author: myitcv

cmd/cue/cmd/vet.go

@@ -54,10 +54,10 @@ a set of definitions to pick from.
 Examples:
 
   # Check files against a CUE file:
-  cue vet foo.cue foo.yaml
+  cue vet -c foo.cue foo.yaml
 
   # Check files against a particular expression
-  cue vet foo.cue lang/en.yaml lang/de.yaml -d '#Translation'
+  cue vet -c foo.cue lang/en.yaml lang/de.yaml -d '#Translation'
 
 More than one expression may be given using multiple -d flags. Each non-CUE
 file must match all expression values.