completion: remove generic "os-only" for platforms

Using `--platform=linux` or `--platform=windows` is not commonly
used (or recommended). Let's remove these from the list of suggested
platforms.

We should tweak this completion further, and sort the list based
on the daemon's platform (putting linux first for a Linux daemon,
and windows first on a Windows daemon), possibly with the correct
architecture (and os-version) included, but we don't yet provide
that information in `/_ping`.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/completion/functions.go

@@ -152,7 +152,6 @@ func NoComplete(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCo
 }
 
 var commonPlatforms = []string{
-	"linux",
 	"linux/386",
 	"linux/amd64",
 	"linux/arm",
@@ -169,10 +168,8 @@ var commonPlatforms = []string{
 	// Not yet supported
 	"linux/riscv64",
 
-	"windows",
 	"windows/amd64",
 
-	"wasip1",
 	"wasip1/wasm",
 }