More doc on env var for PowerShell (#157) #410

Job	Run time
rust_clippy_check_windows	1m 43s
build_static_and_test_ubuntu (release/6.0, nightly, no valgrind)	5m 43s
build_static_and_test_ubuntu (release/6.0, 1.70.0, no valgrind)	5m 29s
build_static_and_test_ubuntu (release/6.1, nightly, valgrind)	1h 11m 22s
build_static_and_test_ubuntu (release/6.1, nightly, no valgrind)	6m 28s
rust_clippy_check_ubuntu	4m 52s
docs_rs_check	1m 19s
build_dynamic_and_test_windows_pre	6m 9s
build_static_and_test_ubuntu (release/6.1, 1.70.0, no valgrind)	5m 42s
rustfmt_check (macos-latest)	11s
rustfmt_check (windows-latest)	36s
rustfmt_check (ubuntu-latest)	4s
build_dynamic_and_test_windows (nightly)	2m 31s
build_dynamic_and_test_windows (1.70.0)	1m 51s
	1h 54m 0s

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