rename non-camel-case vars, refactor, satisfy linter

version.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 )
 
-// A version struct holding the sway wm version
+// Version stores the sway wm version
 type Version struct {
 	HumanReadable string `json:"human_readable"`
 	Major         int    `json:"major"`
@@ -13,9 +13,9 @@ type Version struct {
 	Patch         int    `json:"patch"`
 }
 
-// Get the sway software version
+// GetVersion returns the sway software version
 func (ipc *SwayIPC) GetVersion() (*Version, error) {
-	payload, err := ipc.get(GET_VERSION)
+	payload, err := ipc.get(MsgGetVersion)
 	if err != nil {
 		return nil, err
 	}