Improve color support for xterm compatible terminals

Author: tucksaun

colors.go

@@ -19,8 +19,11 @@
 
 package terminal
 
-import "os"
+import (
+	"os"
+	"strings"
+)
 
 func HasPosixColorSupport() bool {
-	return os.Getenv("ANSICON") != "" || os.Getenv("ConEmuANSI") == "ON" || os.Getenv("TERM") == "xterm" || os.Getenv("SHLVL") != ""
+	return os.Getenv("ANSICON") != "" || os.Getenv("ConEmuANSI") == "ON" || strings.HasPrefix(os.Getenv("TERM"), "xterm") || os.Getenv("SHLVL") != ""
 }