Add zellij action new-tab completions (nushell#821)

This PR add completions for this `zellij action new-tab` command, which
is currently missing.

custom-completions/zellij/zellij-completions.nu

@@ -81,6 +81,23 @@ def "nu-complete sessions" [] {
  ^zellij ls -n | lines | parse "{value} {description}"
 }
 
+def "nu-complete zellij layouts" [] {
+ let layout_dir = if 'ZELLIJ_CONFIG_DIR' in $env {
+ [$env.ZELLIJ_CONFIG_DIR "layouts"] | path join
+ } else {
+ match $nu.os-info.name {
+ "linux" => "~/.config/zellij/layouts/"
+ "mac" => "~/Library/Application Support/org.Zellij-Contributors.Zellij/layouts"
+ _ => (error make { msg: "Unsupported OS for zellij" })
+ }
+ }
+
+ ls ( $layout_dir | path expand )
+ | where name =~ "\\.kdl" 
+ | get name 
+ | each { |$it| { value: ($it | path basename | str replace ".kdl" ""), description: $it } }
+}
+
 # Turned off since it messes with sub-commands
 #export extern "zellij" [
 # command?: string@"nu-complete zellij"
@@ -106,6 +123,15 @@ export extern "zellij action rename-tab" [
  name: string # Name for the tab
 ]
 
+# Create a new tab, optionally with a specified tab layout and name
+export extern "zellij action new-tab" [
+ --cwd(-c): path # Change the working directory of the new tab
+ --help(-h) # Print help information
+ --layout(-l): string@"nu-complete zellij layouts" # Layout ot use for the new tab
+ --layout-dir: path # Default folder to look for layouts
+ --name(-n): string # Name for the tab
+]
+
 # Attach to a session
 export extern "zellij attach" [
  session_name: string@"nu-complete sessions" # Name of the session to attach to