licensing: add missing license headers on translation files

Also make the headers more alike for consistency.

po/fi.po

@@ -1,6 +1,6 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the systemd package.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Finnish translation of systemd.
 # Jan Kuparinen <copper_fin@hotmail.com>, 2021.
 msgid ""
 msgstr ""

po/kab.po

@@ -1,6 +1,6 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the systemd package.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Kabyle translation of systemd.
 # Slimane Selyan Amiri <selyan.kab@gmail.com>, 2021.
 msgid ""
 msgstr ""

po/nl.po

@@ -1,6 +1,6 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the systemd package.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Dutch translation of systemd.
 # Pjotr Vertaalt <pjotrvertaalt@gmail.com>, 2021.
 msgid ""
 msgstr ""

po/pt.po

@@ -1,6 +1,6 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the systemd package.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Portuguese translation of systemd.
 # Hugo Carvalho <hugokarvalho@hotmail.com>, 2021.
 msgid ""
 msgstr ""

po/si.po

@@ -1,6 +1,6 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the systemd package.
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Sinhala translation of systemd.
 # Hela Basa <r45xveza@pm.me>, 2021.
 msgid ""
 msgstr ""

po/sr.po

@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 #
-# SOME DESCRIPTIVE TITLE.
-# This file is distributed under the same license as the PACKAGE package.
+# Serbian translation of systemd.
 # Frantisek Sumsal <frantisek@sumsal.cz>, 2021.
 msgid ""
 msgstr ""

po/systemd.pot

@@ -1,7 +1,4 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the systemd package.
-# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+# SPDX-License-Identifier: LGPL-2.1-or-later
 #
 #, fuzzy
 msgid ""

po/uk.po

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
+#
 # Ukrainian translation for systemd.
 # Eugene Melnik <jeka7js@gmail.com>, 2014.
 # Daniel Korostil <ted.korostiled@gmail.com>, 2014, 2016, 2018.

po/zh_CN.po

@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 #
 # Simplified Chinese translation for systemd.
-#
 # Frank Hill <hxf.prc@gmail.com>, 2014.
 # Boyuan Yang <073plan@gmail.com>, 2015.
 # Jeff Bai <jeffbai@aosc.xyz>, 2016.