core: fix and normalize error messages

src/core/hook/wee-hook-command.c

@@ -278,8 +278,8 @@ hook_command (struct t_weechat_plugin *plugin, const char *command,
     if (hook_command_search (plugin, command))
     {
         gui_chat_printf (NULL,
-                         _("%sError: another command \"%s\" already exists "
-                           "for plugin \"%s\""),
+                         _("%sAnother command \"%s\" already exists for "
+                           "plugin \"%s\""),
                          gui_chat_prefix[GUI_CHAT_PREFIX_ERROR],
                          command,
                          plugin_get_name (plugin));

src/core/hook/wee-hook-fd.c

@@ -202,8 +202,8 @@ hook_fd_exec ()
                 {
                     HOOK_FD(ptr_hook, error) = errno;
                     gui_chat_printf (NULL,
-                                     _("%sError: bad file descriptor (%d) "
-                                       "used in hook_fd"),
+                                     _("%sBad file descriptor (%d) used in "
+                                       "hook_fd"),
                                      gui_chat_prefix[GUI_CHAT_PREFIX_ERROR],
                                      HOOK_FD(ptr_hook, fd));
                 }