CutLine: remove lastCutTime feature

The lastCutTime feature (reset the clipboard instead of appending to the
clipboard if the last CutLine was more than 10 seconds ago) was
implemented 8 years ago but was always buggy and never really worked,
until we have accidentally found and fixed the bug just now. No one ever
complained or noticed that, which means it is not a very useful feature.
Fixing it changes the existing behavior (essentially adds a new feature
which did not really exist before) and there is no reason to assume that
this new behavior will be welcome by users. So it's better to remove
this feature.

internal/action/actions.go

@@ -1243,7 +1243,7 @@ func (h *BufPane) CutLine() bool {
 		return false
 	}
 	totalLines := nlines
-	if h.freshClip && time.Since(h.lastCutTime) < 10*time.Second {
+	if h.freshClip {
 		if clip, err := clipboard.Read(clipboard.ClipboardReg); err != nil {
 			InfoBar.Error(err)
 			return false
@@ -1255,7 +1255,6 @@ func (h *BufPane) CutLine() bool {
 		h.Cursor.CopySelection(clipboard.ClipboardReg)
 	}
 	h.freshClip = true
-	h.lastCutTime = time.Now()
 	h.Cursor.DeleteSelection()
 	h.Cursor.ResetSelection()
 	h.Cursor.StoreVisualX()

internal/action/bufpane.go

@@ -231,10 +231,6 @@ type BufPane struct {
 	lastClickTime time.Time
 	lastLoc       buffer.Loc
 
-	// lastCutTime stores when the last ctrl+k was issued.
-	// It is used for clearing the clipboard to replace it with fresh cut lines.
-	lastCutTime time.Time
-
 	// freshClip returns true if one or more lines have been cut to the clipboard
 	// and have never been pasted yet.
 	freshClip bool