[FLINK-8524] Fix TypeExtractor.getBinaryReturnType JavaDoc

The JavaDoc stated that the parameter `lambdaOutputTypeArgumentIndices` was a
table of indices of the type argument specifying the input type, where it
actually is a table of indices of the type argument specifying the output
type. This is now fixed.

This closes apache#5382.

flink-core/src/main/java/org/apache/flink/api/java/typeutils/TypeExtractor.java

@@ -653,7 +653,7 @@ public static <IN, OUT> TypeInformation<OUT> getUnaryOperatorReturnType(
  * @param outputTypeArgumentIndex Index of output type in the class specification
  * @param lambdaInput1TypeArgumentIndices Table of indices of the type argument specifying the first input type. See example.
  * @param lambdaInput2TypeArgumentIndices Table of indices of the type argument specifying the second input type. See example.
- * @param lambdaOutputTypeArgumentIndices Table of indices of the type argument specifying the input type. See example.
+ * @param lambdaOutputTypeArgumentIndices Table of indices of the type argument specifying the output type. See example.
  * @param in1Type Type of the left side input elements (In case of an iterable, it is the element type)
  * @param in2Type Type of the right side input elements (In case of an iterable, it is the element type)
  * @param functionName Function name