Allow shader names with underscores

kitty/blit_vertex.glsl

@@ -1,2 +1,2 @@
 uniform vec4 src_rect, dest_rect;
-#pragma kitty_include_shader <blit_common_vertex.glsl>
+#pragma kitty_include_shader <blit_common.glsl>

kitty/graphics_vertex.glsl

@@ -1,2 +1,2 @@
 uniform vec4 src_rect, dest_rect;
-#pragma kitty_include_shader <blit_common_vertex.glsl>
+#pragma kitty_include_shader <blit_common.glsl>

setup.py

@@ -1151,7 +1151,7 @@ def find_uniform_names(raw: str) -> Iterator[str]:
 
     for x in sorted(glob.glob('kitty/*.glsl')):
         name = os.path.basename(x).partition('.')[0]
-        name, sep, shader_type = name.partition('_')
+        name, sep, shader_type = name.rpartition('_')
         if not sep or shader_type not in ('fragment', 'vertex'):
             continue
         class_names[name] = f'{name.capitalize()}Uniforms'