docs: Use numbered list for env setup in Contribution Guide #4467

Job	Run time
Compile Native Binaries (linux-x64)	13s
Compile Native Binaries (linux-arm)	15s
Compile Native Binaries (macos-x64)	21s
Compile Native Binaries (macos-arm)	17s
Compile Native Binaries (windows-x64)	22s
Lint and Prune / Lint and Prune	3m 5s
Build Docs / Build Docs	5m 17s
Features Tests / test	5m 31s
Stress Tests (No Reuse V8 Context) / stress-test	9m 28s
Stress Tests (Reuse V8 Context) / stress-test	7m 39s
Run Integration Tests (linux-x64, Node 18, Reuse V8 Context false)	7m 17s
Run Integration Tests (linux-arm, Node 18, Reuse V8 Context true)	9m 19s
Run Integration Tests (macos-x64, Node 18, Reuse V8 Context true)	8m 29s
Run Integration Tests (macos-arm, Node 18, Reuse V8 Context true)	6m 16s
Run Integration Tests (windows-x64, Node 18, Reuse V8 Context true)	10m 4s
Run Integration Tests (linux-x64, Node 22, Reuse V8 Context false)	6m 40s
Run Integration Tests (linux-arm, Node 22, Reuse V8 Context true)	9m 38s
Run Integration Tests (macos-x64, Node 22, Reuse V8 Context true)	8m 7s
Run Integration Tests (macos-arm, Node 22, Reuse V8 Context true)	6m 25s
Run Integration Tests (windows-x64, Node 22, Reuse V8 Context true)	10m 45s
	1h 55m 28s

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