hypr: use a single brightnessctl call for the brightness OSD

brightnessctl -m s sets and prints the new percentage in one invocation,
so drop the second brightnessctl call per (repeating) brightness keypress.

dot_config/hypr/hyprland.d.lua/keybinds.lua.tmpl

@@ -377,9 +377,10 @@ hl.bind("XF86AudioPrev",  hl.dsp.exec_cmd("playerctl previous"),   { locked = tr
 -- Brightness — let brightnessctl do the math, then push the new percentage to
 -- the Quickshell OSD (field 4 of `-m` output is the percentage, e.g. "70%").
 local function brightness_step(arg)
+  -- Single brightnessctl call: `-m s` sets and prints the machine line
+  -- (device,class,current,percent,max); field 4 is the new percentage.
   return hl.dsp.exec_cmd(
-    "brightnessctl -e4 -n2 s " .. arg ..
-    " >/dev/null && qs ipc call osd brightness \"$(brightnessctl -m | cut -d, -f4 | tr -d %)\""
+    "qs ipc call osd brightness \"$(brightnessctl -e4 -n2 -m s " .. arg .. " | cut -d, -f4 | tr -d %)\""
   )
 end
 hl.bind("XF86MonBrightnessUp",           brightness_step("1%+"), { locked = true, repeating = true, description = "Brightness up (1%)" })