docs(userspace/libsinsp/filter/parser): fix grammar doc #7330

Job	Run time
build-libs-linux-amd64-static 🎃	23m 12s
build-libs-linux-amd64 😁 (system_deps)	7m 29s
build-libs-others-amd64 😨 (windows-latest, MultiThreaded)	6m 8s
build-libs-linux-amd64 😁 (bundled_deps)	17m 14s
build-libs-others-amd64 😨 (windows-latest, MultiThreadedDLL)	5m 41s
build-shared-libs-linux-amd64 🧐	5m 56s
build-libs-others-amd64 😨 (macos-latest)	2m 21s
build-libs-linux-amd64 😁 (system_deps_minimal)	5m 20s
build-libs-linux-amd64 😁 (sanitizers)	16m 52s
build-shared-libs-macos-amd64 😨	2m 38s
build-libs-linux-amd64 😁 (zig)	26m 18s
build-libs-linux-arm64 😁 (system_deps)	13m 5s
build-libs-linux-arm64 😁 (bundled_deps)	28m 29s
build-libs-emscripten 🧐	5m 33s
build-libs-linux-arm64 😁 (system_deps_minimal)	9m 29s
build-libs-linux-arm64 😁 (sanitizers)	37m 7s
run-e2e-tests-amd64 (system_deps)	9m 35s
build-libs-linux-arm64 😁 (zig)	39m 14s
run-e2e-tests-amd64 (bundled_deps)	19m 50s
run-e2e-tests-amd64 (asan)	21m 6s
test-libs-static (bundled_deps)	14m 1s
	5h 16m 38s

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