[27.x backport] assorted improvements for shell completion

[thaJeztah]

backports:

• Improve completion of containers for docker rm #5527
• add shell-completion for --platform flags #5516
• cli/command/container: add unit tests for completion helpers #5492
• cli/container: use github.com/moby/sys/capability for completions #5480
• cli/command/completion: add more unit-tests #5533

- Description for the changelog

- Improve shell-completion of containers for `docker rm` [docker/cli#5527](https://github.com/docker/cli/pull/5527)
- Add shell-completion for `--platform` flags [docker/cli#5516](https://github.com/docker/cli/pull/5516)
- 

- A picture of a cute animal (not mandatory but encouraged)

[thaJeztah]

Had to apply a small patch in the last commit due to the master branch using a type that was moved;

44.74 # github.com/docker/cli/cli/command/container
44.74 cli/command/container/rm.go:41:84: undefined: container.Summary

diff --git a/cli/command/container/rm.go b/cli/command/container/rm.go
index 12beef64f..b234b6009 100644
--- a/cli/command/container/rm.go
+++ b/cli/command/container/rm.go
@@ -8,6 +8,7 @@ import (
        "github.com/docker/cli/cli"
        "github.com/docker/cli/cli/command"
        "github.com/docker/cli/cli/command/completion"
+       "github.com/docker/docker/api/types"
        "github.com/docker/docker/api/types/container"
        "github.com/docker/docker/errdefs"
        "github.com/pkg/errors"
@@ -38,7 +39,7 @@ func NewRmCommand(dockerCli command.Cli) *cobra.Command {
                Annotations: map[string]string{
                        "aliases": "docker container rm, docker container remove, docker rm",
                },
-               ValidArgsFunction: completion.ContainerNames(dockerCli, true, func(ctr container.Summary) bool {
+               ValidArgsFunction: completion.ContainerNames(dockerCli, true, func(ctr types.Container) bool {
                        return opts.force || ctr.State == "exited" || ctr.State == "created"
                }),
        }

[thaJeztah]

LOL "surprise" there were more places to do the same 😂

65.03 cli/command/completion/functions_test.go:43:21: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:71:37: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:72:32: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:84:28: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:97:28: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:109:28: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:118:30: undefined: container.Summary
65.03 cli/command/completion/functions_test.go:119:30: undefined: container.Summary

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 87.50000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 58.65%. Comparing base (2668b11) to head (b018e55).
Report is 17 commits behind head on 27.x.

Additional details and impacted files

@@            Coverage Diff             @@
##             27.x    #5540      +/-   ##
==========================================
- Coverage   59.77%   58.65%   -1.13%     
==========================================
  Files         345      345              
  Lines       23443    29042    +5599     
==========================================
+ Hits        14014    17035    +3021     
- Misses       8454    11036    +2582     
+ Partials      975      971       -4