[Ada] Rename Ada 202* to Ada 2022

[Ada] Rename Ada 202* to Ada 2022

gcc/ada/

	* einfo.ads, errout.adb, errout.ads, exp_aggr.adb, exp_ch5.adb,
	exp_ch6.adb, exp_ch8.adb, exp_ch9.adb, exp_imgv.adb,
	exp_put_image.adb, fe.h, impunit.adb, impunit.ads,
	libgnat/a-cobove.ads, libgnat/a-convec.ads, opt.ads,
	par-ch12.adb, par-ch3.adb, par-ch4.adb, par-ch5.adb,
	par-ch6.adb, par-prag.adb, par-util.adb, scans.ads, scng.adb,
	sem_aggr.adb, sem_attr.adb, sem_ch10.adb, sem_ch12.adb,
	sem_ch13.adb, sem_ch3.adb, sem_ch5.adb, sem_ch6.adb,
	sem_ch8.adb, sem_elab.adb, sem_eval.adb, sem_prag.adb,
	sem_res.adb, sem_type.adb, sem_util.adb, sem_util.ads,
	sinfo.ads, snames.ads-tmpl, sprint.adb, switch-c.adb, usage.adb,
	doc/gnat_ugn/building_executable_programs_with_gnat.rst,
	doc/gnat_rm/implementation_defined_aspects.rst,
	gcc-interface/trans.c: Update all references to Ada 2020 to Ada
	2022. Rename pragma Ada_2020 to Ada_2022.  Update documentation
	accordingly.
	* gnat_ugn.texi, gnat_rm.texi: Regenerate.