chore: standardize # style headers

Changes made with regex plus some manual tweaks.

Find:
/(?:(?<!#!\/bin\/sh\n)(?:^#\n))*^#.*?[Cc]opyright.*?(\d{4}) *([0-9A-z,_\- ]+).*?\n(?:^#\n)*^#.*?SPDX-License-Identifier:? *(.+) *?\n(?:^#\n)*/gm

Replace:
# Copyright (c) $1 $2
# SPDX-License-Identifier: $3

PR: #564

app/boards/shields/quefrency/Kconfig.defconfig

@@ -1,5 +1,5 @@
-#Copyright (c) 2020 The ZMK Contributors
-#SPDX-License-Identifier: MIT
+# Copyright (c) 2020 The ZMK Contributors
+# SPDX-License-Identifier: MIT
  
  
 if SHIELD_QUEFRENCY_LEFT