copying: scroll just one line when M-6 is pressed on the bottom row

This fixes https://savannah.gnu.org/bugs/?56249.

Bug existed since version 2.6.0, commit 318ed6b1.

src/cut.c

@@ -426,7 +426,8 @@ void do_copy_text(void)
 		openfile->firstcolumn = is_firstcolumn;
 		openfile->current = fsfromline(is_current_lineno);
 		openfile->current_x = is_current_x;
-	}
+	} else
+		focusing = FALSE;
 }
 
 /* Cut from the current cursor position to the end of the file. */