Add documentation to PhysicsDirectBodyState2DExtension #19391

Job	Run time
📊 Static checks / Code style, file formatting, and docs	38s
🤖 Android / Template (target=template_release)	16m 57s
🐧 Linux / Editor w/ Mono (target=editor)	25m 22s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)	24m 53s
🌐 Web / Template (target=template_release)	11m 21s
🏁 Windows / Editor (target=editor, tests=yes)	28m 39s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	22m 48s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	21m 9s
🏁 Windows / Template (target=template_release)	18m 26s
🍎 macOS / Editor (target=editor, tests=yes)	22m 16s
🍎 macOS / Template (target=template_release)	11m 39s
🐧 Linux / Template w/ Mono (target=template_release)	14m 2s
🍏 iOS / Template (target=template_release)	19m 21s
🐧 Linux / Minimal template (target=template_release, everything disabled)	9m 52s
🪲 Godot CPP / Build and test Godot CPP	6m 43s
	4h 14m 6s

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