cli-plugins/manager: remove deprecated metadata aliases

These consts and types were moved to a separate metadata package in commits
292713c887 and 4321293972,
and deprecated in 72f76f2720, 5876b2941c,
and 6fa7d18320.

This removes the deprecated aliases in `cli-plugins/manager` in favor of
their equivalent in `cli-plugins/manager/metadata`:

- `CommandAnnotationPlugin`
- `CommandAnnotationPluginVendor`
- `CommandAnnotationPluginVersion`
- `CommandAnnotationPluginInvalid`
- `CommandAnnotationPluginCommandPath`
- `NamePrefix`
- `MetadataSubcommandName`
- `HookSubcommandName`
- `Metadata`
- `ReexecEnvvar`

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

cli-plugins/manager/manager.go

@@ -18,16 +18,6 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
-const (
-	// ReexecEnvvar is the name of an ennvar which is set to the command
-	// used to originally invoke the docker CLI when executing a
-	// plugin. Assuming $PATH and $CWD remain unchanged this should allow
-	// the plugin to re-execute the original CLI.
-	//
-	// Deprecated: use [metadata.ReexecEnvvar]. This alias will be removed in the next release.
-	ReexecEnvvar = metadata.ReexecEnvvar
-)
-
 // errPluginNotFound is the error returned when a plugin could not be found.
 type errPluginNotFound string