meson: drop explicit custom_target names

[1] says:
> Since 0.60.0 the name argument is optional and defaults to the basename of
> the first output
We specify >= 0.62 as the supported version, so drop the duplicate name in all cases
where it is the same as outputs[0], i.e. almost all cases.

[1] https://mesonbuild.com/Reference-manual_functions.html#custom_target

sysctl.d/meson.build

@@ -13,7 +13,6 @@ if cc.sizeof('long') > 4
 endif
 
 custom_target(
-        '50-coredump.conf',
         input : '50-coredump.conf.in',
         output : '50-coredump.conf',
         command : [jinja2_cmdline, '@INPUT@', '@OUTPUT@'],