User nerd font symbols for progress as they are guaranteed to exist

kitty/tab_bar.py

@@ -232,14 +232,14 @@ class TabAccessor:
         if w is None:
             return ''
         if w.progress.state is ProgressState.error:
-            return '\u26a0\ufe0f '
+            return '  '
         if w.progress.state is ProgressState.unset:
             return ''
         if w.progress.state is ProgressState.indeterminate:
-            return '🔄 '
+            return '  '
         p = f'{w.progress.percent}% '
         if w.progress.state is ProgressState.paused:
-            return f'⏸  {p}'
+            return f'  {p}'
         return p
 
     @property

kitty/window.py

@@ -89,11 +89,11 @@ from .fast_data_types import (
     wakeup_main_loop,
 )
 from .keys import keyboard_mode_name, mod_mask
+from .progress import Progress
 from .rgb import to_color
 from .terminfo import get_capabilities
 from .types import MouseEvent, OverlayType, WindowGeometry, ac, run_once
 from .typing import BossType, ChildType, EdgeLiteral, TabType, TypedDict
-from .progress import Progress
 from .utils import (
     color_as_int,
     docs_url,