Build : using go:generate and go:embed (#2195)

* using go:generate and go:embed

* fix import

runtime/runtime.go

@@ -0,0 +1,31 @@
+package config
+
+import (
+	"embed"
+	"strings"
+)
+
+//go:generate go run syntax/make_headers.go syntax
+
+//go:embed colorschemes help plugins syntax
+var runtime embed.FS
+
+// AssetDir lists file names in folder
+func AssetDir(name string) ([]string, error) {
+	name = strings.TrimLeft(name, "runtime/")
+	entries, err := runtime.ReadDir(name)
+	if err != nil {
+		return nil, err
+	}
+	names := make([]string, len(entries), len(entries))
+	for i, entry := range entries {
+		names[i] = entry.Name()
+	}
+	return names, nil
+}
+
+// Asset returns a file content
+func Asset(name string) ([]byte, error) {
+	name = strings.TrimLeft(name, "runtime/")
+	return runtime.ReadFile(name)
+}