actions: Use SetOptionNative() instead of setting options directly

Setting options directly in (h.)Buf.Settings without calling SetOption() or
SetOptionNative() is generally not the best idea, since it may not
trigger the needed side effects.
In particular, after https://github.com/zyedidia/micro/pull/3343,
directly setting `diffgutter` and `ruler` causes them not being tracked as
locally overridden per buffer, so if we run the `reload` command,
it unexpectedly replaces them with the default ones.

internal/action/actions.go

@@ -1794,12 +1794,12 @@ func (h *BufPane) HalfPageDown() bool {
 
 // ToggleDiffGutter turns the diff gutter off and on
 func (h *BufPane) ToggleDiffGutter() bool {
-	if !h.Buf.Settings["diffgutter"].(bool) {
+	diffgutter := !h.Buf.Settings["diffgutter"].(bool)
-		h.Buf.Settings["diffgutter"] = true
+	h.Buf.SetOptionNative("diffgutter", diffgutter)
+	if diffgutter {
 		h.Buf.UpdateDiff()
 		InfoBar.Message("Enabled diff gutter")
 	} else {
-		h.Buf.Settings["diffgutter"] = false
 		InfoBar.Message("Disabled diff gutter")
 	}
 	return true
@@ -1807,11 +1807,11 @@ func (h *BufPane) ToggleDiffGutter() bool {
 
 // ToggleRuler turns line numbers off and on
 func (h *BufPane) ToggleRuler() bool {
-	if !h.Buf.Settings["ruler"].(bool) {
+	ruler := !h.Buf.Settings["ruler"].(bool)
-		h.Buf.Settings["ruler"] = true
+	h.Buf.SetOptionNative("ruler", ruler)
+	if ruler {
 		InfoBar.Message("Enabled ruler")
 	} else {
-		h.Buf.Settings["ruler"] = false
 		InfoBar.Message("Disabled ruler")
 	}
 	return true