Clarify documentation for completion

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

shell_completions.md

@@ -148,8 +148,8 @@ cmd := &cobra.Command{
 	Use:   "status RELEASE_NAME",
 	Short: "Display the status of the named release",
 	Long:  status_long,
-	RunE: func(cmd *cobra.Command, args []string) {
-		RunGet(args[0])
+	Run: func(cmd *cobra.Command, args []string) {
+		RunStatus(args[0])
 	},
 	ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 		if len(args) != 0 {
@@ -159,13 +159,14 @@ cmd := &cobra.Command{
 	},
 }
 ```
-Where `getReleasesFromCluster()` is a Go function that obtains the list of current Helm releases running on the Kubernetes cluster.
-Notice we put the `ValidArgsFunction` on the `status` sub-command. Let's assume the Helm releases on the cluster are: `harbor`, `notary`, `rook` and `thanos` then this dynamic completion will give results like:
+Where `getReleasesFromCluster()` is a Go function that returns the list of current Helm release names running on the Kubernetes cluster.
+Similarly as for `Run`, the `args` parameter represents the arguments present on the command-line, while the `toComplete` parameter represents the final argument which the user is trying to complete (e.g., `helm status th<TAB>` will have `toComplete` be `"th"`); the `toComplete` parameter will be empty when the user has requested completions right after typing a space (e.g., `helm status <TAB>`). Notice we put the `ValidArgsFunction` on the `status` sub-command, as it provides completions for this sub-command specifically. Let's assume the Helm releases on the cluster are: `harbor`, `notary`, `rook` and `thanos` then this dynamic completion will give results like:
 
 ```bash
 $ helm status [tab][tab]
 harbor notary rook thanos
 ```
+
 You may have noticed the use of `cobra.ShellCompDirective`.  These directives are bit fields allowing to control some shell completion behaviors for your particular completion.  You can combine them with the bit-or operator such as `cobra.ShellCompDirectiveNoSpace | cobra.ShellCompDirectiveNoFileComp`
 ```go
 // Indicates that the shell will perform its default behavior after completions
@@ -324,7 +325,7 @@ cmd.RegisterFlagCompletionFunc(flagName, func(cmd *cobra.Command, args []string,
 ```
 ### Descriptions for completions
 
-`zsh`, `fish` and `powershell` allow for descriptions to annotate completion choices.  For commands and flags, Cobra will provide the descriptions automatically, based on usage information.  For example, using zsh:
+`zsh`, `fish` and `powershell` support descriptions for completion choices.  For commands and flags, Cobra will provide the descriptions automatically, based on usage information.  For example, using zsh:
 ```
 $ helm s[tab]
 search  -- search for a keyword in charts
@@ -337,7 +338,7 @@ $ helm s[tab]
 search  (search for a keyword in charts)  show  (show information of a chart)  status  (displays the status of the named release)
 ```
 
-Cobra allows you to add annotations to your own completions.  Simply add the annotation text after each completion, following a `\t` separator.  This technique applies to completions returned by `ValidArgs`, `ValidArgsFunction` and `RegisterFlagCompletionFunc()`.  For example:
+Cobra allows you to add descriptions to your own completions.  Simply add the description text after each completion, following a `\t` separator.  This technique applies to completions returned by `ValidArgs`, `ValidArgsFunction` and `RegisterFlagCompletionFunc()`.  For example:
 ```go
 ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 	return []string{"harbor\tAn image registry", "thanos\tLong-term metrics"}, cobra.ShellCompDirectiveNoFileComp