Add links from Rust and C++ to the common platform backend docs #11203

Job	Run time
cpp_cmake (ubuntu-22.04)	9m 48s
cpp_cmake (macos-12)	12m 47s
cpp_cmake (windows-2022)	12m 14s
build_and_test (ubuntu-22.04, stable)	14m 43s
build_and_test (ubuntu-22.04, 1.66)	18m 47s
build_and_test (macos-11, stable)	10m 58s
build_and_test (windows-2022, stable)	11m 29s
build_and_test (windows-2022, 1.66)	21m 49s
esp-idf	52m 25s
cpp_test_driver (ubuntu-22.04)	9m 20s
cpp_test_driver (macos-12)	8m 51s
cpp_test_driver (windows-2022)	10m 40s
ffi_32bit_build	1m 53s
mcu (pico-st7789, thumbv6m-none-eabi)	59s
mcu (stm32h735g, thumbv7em-none-eabihf)	1m 13s
fmt_test	1m 31s
mcu_esp	2m 55s
napi_test (ubuntu-22.04)	6m 28s
napi_test (macos-11)	7m 27s
napi_test (windows-2022)	5m 43s
tree-sitter	12s
node_test (ubuntu-22.04)	3m 18s
node_test (macos-11)	3m 40s
uefi-demo	1m 0s
updater_test (0.3.0)	2m 13s
wasm / wasm	2m 57s
docs / docs	9m 22s
wasm_demo / wasm_demo	15m 25s
wasm / build-slintpad	1m 1s
wasm / lint-slintpad	35s
cpp_package_test	2m 31s
	4h 24m 14s

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