all: move description of C files below the copyright and license

src/core/core-command.c

@@ -1,6 +1,4 @@
 /*
- * core-command.c - WeeChat core commands
- *
  * SPDX-FileCopyrightText: 2003-2025 Sébastien Helleu <flashcode@flashtux.org>
  * SPDX-FileCopyrightText: 2005-2006 Emmanuel Bouthenot <kolter@openics.org>
  *
@@ -22,6 +20,8 @@
  * along with WeeChat.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+/* WeeChat core commands */
+
 /* this define is needed for strptime() (not on OpenBSD/Sun) */
 #if !defined(__OpenBSD__) && !defined(__sun)
 #define _XOPEN_SOURCE 700