[jnigen] Fix doclet type parameter parsing (#1960) #596

Job	Run time
analyze_jnigen (stable)	50s
build_jni_example_windows	2m 32s
analyze_jni	1m 10s
build_jni_example_android	3m 31s
build_jni_example_linux	2m 51s
run_pdfbox_example_linux	3m 31s
test_jnigen_macos_minimal	3m 17s
test_jnigen_windows_minimal	8m 10s
test_jnigen (ubuntu-latest, stable)	8m 26s
test_jnigen (ubuntu-latest, beta)	9m 23s
test_jni	1m 55s
test_jni_macos_minimal	1m 22s
test_jni_windows_minimal	4m 15s
coveralls_finish	4s
	51m 17s

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