A comment added to IndexSearcherInternal.cpp, requested in pull request by Chen.
A comment added to IndexSearcherInternal.cpp, requested in pull request by Chen.

SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn