[IDL] Assume readwrite is the default for attributes

[andy31415]

Problem

Based on side discussion with @tcarmelveilleux : readwrite should be assumed default. Added 'readonly' as the only special marker for now and added a TODO for eventual 'writeonly' support which I do not believe zap supports.

Change overview

IDL change to only show readonly. Placed it in front instead of brackets.

Testing

Manual IDL generation and review. CI will also validate.

[github-actions]

PR #13707: Size comparison from 41d3a6c to 2e89cc2

Full report (32 builds for efr32, esp32, k32w, linux, mbed, nrfconnect, p6, qpg, telink)

platform	target	config	section	41d3a6c	2e89cc2	change	% change
efr32	lighting-app	BRD4161A	(read only)	834948	834948	0	0.0
			(read/write)	127636	127636	0	0.0
			.bss	125744	125744	0	0.0
			.data	1892	1892	0	0.0
			.text	834940	834940	0	0.0
		BRD4161A+rpc	(read only)	822352	822352	0	0.0
			(read/write)	144296	144296	0	0.0
			.bss	142304	142304	0	0.0
			.data	1992	1992	0	0.0
			.text	822344	822344	0	0.0
	window-app	BRD4161A	(read only)	805536	805536	0	0.0
			(read/write)	126328	126328	0	0.0
			.bss	124480	124480	0	0.0
			.data	1844	1844	0	0.0
			.text	805528	805528	0	0.0
esp32	all-clusters-app	c3devkit	(read only)	912352	912352	0	0.0
			(read/write)	1316698	1316698	0	0.0
			.dram0.bss	70528	70528	0	0.0
			.dram0.data	14292	14292	0	0.0
			.flash.rodata	178384	178384	0	0.0
			.flash.text	912352	912352	0	0.0
			.iram0.text	62056	62056	0	0.0
		m5stack	(read only)	961231	961231	0	0.0
			(read/write)	448856	448856	0	0.0
			.dram0.bss	74984	74984	0	0.0
			.dram0.data	34072	34072	0	0.0
			.flash.rodata	207672	207672	0	0.0
			.flash.text	955847	955847	0	0.0
			.iram0.text	123399	123399	0	0.0
k32w	light	k32w061+release	(read/write)	659156	659156	0	0.0
			.bss	77136	77136	0	0.0
			.data	1860	1860	0	0.0
			.text	574360	574360	0	0.0
	lock	k32w061+release	(read/write)	661888	661888	0	0.0
			.bss	77432	77432	0	0.0
			.data	1880	1880	0	0.0
			.text	576776	576776	0	0.0
linux	chip-tool-ipv6only	arm64	(read only)	8123116	8123116	0	0.0
			(read/write)	374225	374225	0	0.0
			.bss	55217	55217	0	0.0
			.data	1112	1112	0	0.0
			.data.rel.ro	248696	248696	0	0.0
			.dynamic	560	560	0	0.0
			.got	65504	65504	0	0.0
			.init	24	24	0	0.0
			.init_array	168	168	0	0.0
			.rodata	422244	422244	0	0.0
			.text	6903204	6903204	0	0.0
	thermostat-no-ble	arm64	(read only)	2044220	2044220	0	0.0
			(read/write)	145985	145985	0	0.0
			.bss	65089	65089	0	0.0
			.data	896	896	0	0.0
			.data.rel.ro	73016	73016	0	0.0
			.dynamic	560	560	0	0.0
			.got	4048	4048	0	0.0
			.init	24	24	0	0.0
			.init_array	304	304	0	0.0
			.rodata	129932	129932	0	0.0
			.text	1699680	1699680	0	0.0
mbed	all-clusters-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2350112	2350112	0	0.0
			.bss	189220	189220	0	0.0
			.data	5328	5328	0	0.0
			.text	1312688	1312688	0	0.0
	lighting-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2334568	2334568	0	0.0
			.bss	180760	180760	0	0.0
			.data	5576	5576	0	0.0
			.text	1297168	1297168	0	0.0
	lock-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2304984	2304984	0	0.0
			.bss	179768	179768	0	0.0
			.data	5552	5552	0	0.0
			.text	1267584	1267584	0	0.0
	pigweed-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	1139712	1139712	0	0.0
			.bss	11756	11756	0	0.0
			.data	4368	4368	0	0.0
			.text	103096	103096	0	0.0
	shell	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2054464	2054464	0	0.0
			.bss	156876	156876	0	0.0
			.data	4864	4864	0	0.0
			.text	1017064	1017064	0	0.0
nrfconnect	lighting-app	nrf52840dk_nrf52840	(read/write)	943491	943491	0	0.0
			bss	119628	119628	0	0.0
			rodata	108824	108824	0	0.0
			text	637448	637448	0	0.0
		nrf52840dk_nrf52840+rpc	(read/write)	928975	928975	0	0.0
			bss	116672	116672	0	0.0
			rodata	101276	101276	0	0.0
			text	632844	632844	0	0.0
		nrf52840dongle_nrf52840	(read/write)	994171	994171	0	0.0
			bss	122472	122472	0	0.0
			rodata	113580	113580	0	0.0
			text	669648	669648	0	0.0
		nrf5340dk_nrf5340_cpuapp	(read/write)	853318	853318	0	0.0
			bss	116416	116416	0	0.0
			rodata	102000	102000	0	0.0
			text	554372	554372	0	0.0
	lock-app	nrf52840dk_nrf52840	(read/write)	912851	912851	0	0.0
			bss	118784	118784	0	0.0
			rodata	103792	103792	0	0.0
			text	612896	612896	0	0.0
		nrf5340dk_nrf5340_cpuapp	(read/write)	822922	822922	0	0.0
			bss	115600	115600	0	0.0
			rodata	97020	97020	0	0.0
			text	529856	529856	0	0.0
	pigweed-app	nrf52840dk_nrf52840	(read/write)	541835	541835	0	0.0
			bss	52588	52588	0	0.0
			rodata	50104	50104	0	0.0
			text	376940	376940	0	0.0
	pump-app	nrf52840dk_nrf52840	(read/write)	915703	915703	0	0.0
			bss	118548	118548	0	0.0
			rodata	104156	104156	0	0.0
			text	615548	615548	0	0.0
	pump-controller-app	nrf52840dk_nrf52840	(read/write)	910787	910787	0	0.0
			bss	118572	118572	0	0.0
			rodata	103264	103264	0	0.0
			text	611472	611472	0	0.0
	shell	nrf52840dk_nrf52840	(read/write)	798655	798655	0	0.0
			bss	109776	109776	0	0.0
			rodata	78388	78388	0	0.0
			text	533984	533984	0	0.0
		nrf5340dk_nrf5340_cpuapp	(read/write)	711454	711454	0	0.0
			bss	107664	107664	0	0.0
			rodata	72688	72688	0	0.0
			text	451660	451660	0	0.0
p6	all-clusters-app	default	(read/write)	2405304	2405304	0	0.0
			.bss	117556	117556	0	0.0
			.data	2608	2608	0	0.0
			.text	1363568	1363568	0	0.0
	light-app	default	(read/write)	2330160	2330160	0	0.0
			.bss	106128	106128	0	0.0
			.data	2400	2400	0	0.0
			.text	1288424	1288424	0	0.0
	lock-app	default	(read/write)	2299184	2299184	0	0.0
			.bss	104976	104976	0	0.0
			.data	2352	2352	0	0.0
			.text	1257448	1257448	0	0.0
qpg	lighting-app	qpg6105+debug	(read only)	565152	565152	0	0.0
			(read/write)	146940	146940	0	0.0
			.bss	89960	89960	0	0.0
			.data	1056	1056	0	0.0
			.text	559832	559832	0	0.0
	lock-app	qpg6105+debug	(read only)	515564	515564	0	0.0
			(read/write)	146936	146936	0	0.0
			.bss	88584	88584	0	0.0
			.data	980	980	0	0.0
			.text	510244	510244	0	0.0
	persistent-storage-app	qpg6105+debug	(read only)	106848	106848	0	0.0
			(read/write)	146940	146940	0	0.0
			.bss	38512	38512	0	0.0
			.data	288	288	0	0.0
			.text	101528	101528	0	0.0
telink	lighting-app	tlsr9518adk80d	(read/write)	840886	840886	0	0.0
			bss	87316	87316	0	0.0
			noinit	37160	37160	0	0.0
			text	587842	587842	0	0.0

[andy31415]

fast track: IDL changes are free form text really, do not affect SDK workings.