overlays: Add kitty duplicate lines patch

Patches the issue described below:
https://github.com/kovidgoyal/kitty/issues/6306

overlays/default.nix

@@ -2,6 +2,7 @@
   imports = [
     ./alejandra
     ./joshuto
+    ./kitty
     ./rofi
   ];
 }

overlays/kitty/default.nix

@@ -0,0 +1,9 @@
+{
+  nixpkgs.overlays = [
+    (final: prev: {
+      kitty = prev.kitty.overrideAttrs (old: {
+        patches = (old.patches or []) ++ [./fix-duplicate-lines.patch];
+      });
+    })
+  ];
+}

overlays/kitty/fix-duplicate-lines.patch

@@ -0,0 +1,40 @@
+From 7f6f1f9a5dac301b9f977e0d1a53c487c5cad9aa Mon Sep 17 00:00:00 2001
+From: Kovid Goyal <kovid@kovidgoyal.net>
+Date: Sun, 28 May 2023 06:24:49 +0530
+Subject: [PATCH] Fix a regression in 0.28.0 that caused a buffer overflow when
+ clearing the screen
+
+Fixes #6306
+Fixes #6308
+---
+ docs/changelog.rst | 2 ++
+ kitty/screen.c     | 3 ++-
+ 2 files changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/docs/changelog.rst b/docs/changelog.rst
+index b8c9a049e8..12f9806fa2 100644
+--- a/docs/changelog.rst
++++ b/docs/changelog.rst
+@@ -71,6 +71,8 @@ Detailed list of changes
+ 
+ - Graphics: Move images up along with text when the window is shrunk vertically (:iss:`6278`)
+ 
++- Fix a regression in 0.28.0 that caused a buffer overflow when clearing the screen (:iss:`6306`, :pull:`6308`)
++
+ 0.28.1 [2023-04-21]
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ 
+diff --git a/kitty/screen.c b/kitty/screen.c
+index ffa0e9f94d..a73e4084e3 100644
+--- a/kitty/screen.c
++++ b/kitty/screen.c
+@@ -894,7 +894,8 @@ cursor_within_margins(Screen *self) {
+ static void
+ screen_dirty_line_graphics(Screen *self, unsigned int top, unsigned int bottom) {
+     bool need_to_remove = false;
+-    for (unsigned int y = top; y <= bottom; y++) {
++    bottom = MIN(bottom+1, self->lines);
++    for (unsigned int y = top; y < bottom; y++) {
+         if (self->linebuf->line_attrs[y].has_image_placeholders) {
+             need_to_remove = true;
+             linebuf_mark_line_dirty(self->linebuf, y);