Merge branch 'fix/4131' into dev

Author: Neko-Box-Coder

internal/buffer/buffer.go

@@ -690,6 +690,9 @@ func (b *Buffer) WordAt(loc Loc) []byte {
 // Shared returns if there are other buffers with the same file as this buffer
 func (b *Buffer) Shared() bool {
 	for _, buf := range OpenBuffers {
+		if buf == nil {
+			continue
+		}
 		if buf != b && buf.SharedBuffer == b.SharedBuffer {
 			return true
 		}