Revert "Disable ONLCR mapping of NL output to CR-NL"

This reverts commit 3f820f0edf.
While the premise described by @nbuwe is sound in #4505, we are now
apparently relying on this behavior is some places (although
inadvertently as there doesn't seem to be a deliberate acknowledgement
of that anywhere).

Turning off ONLCR causes things like indented multiline commands to not
appear correct at the tty (subsequent lines appear both at column 0 and
again indented).

src/reader.cpp

@@ -924,7 +924,6 @@ void reader_init() {
     shell_modes.c_iflag &= ~INLCR;  // disable mapping NL (\cJ) to CR (\cM)
     shell_modes.c_iflag &= ~IXON;   // disable flow control
     shell_modes.c_iflag &= ~IXOFF;  // disable flow control
-    shell_modes.c_iflag &= ~ONLCR;  // disable mapping of NL to CR-NL on output (#4505)
 
     shell_modes.c_lflag &= ~ICANON;  // turn off canonical mode
     shell_modes.c_lflag &= ~ECHO;    // turn off echo mode

src/screen.cpp

@@ -488,6 +488,13 @@ static void s_move(screen_t *s, data_buffer_t *b, int new_x, int new_y) {
 
     y_steps = new_y - s->actual.cursor.y;
 
+    if (y_steps > 0 && (strcmp(cursor_down, "\n") == 0)) {
+        // This is very strange - it seems some (all?) consoles use a simple newline as the cursor
+        // down escape. This will of course move the cursor to the beginning of the line as well as
+        // moving it down one step. The cursor_up does not have this behaviour...
+        s->actual.cursor.x = 0;
+    }
+
     if (y_steps < 0) {
         str = cursor_up;
     } else {