refactor(commands): separate commands and its core into two folders (#32)

- I think it would be better if one for commands only, one for the spec
handling core logic so people won't be confused by the core logic inside
the commands folder (cleaner I guess)
- Regen docs

commands/view/zed.go

@@ -1,14 +1,14 @@
 package view
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "zed",
 		Description: "A lightning-fast, collaborative code editor written in Rust",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-h", Description: "Print help information"},
 			{Name: "-v", Description: "Print Zed's version and the app path"},
 			{Name: "-w", Description: "Wait for all of the given paths to be closed before exiting"},