Fixes a documentation error regarding the return type/value
Fixes a documentation error regarding the return type/value

Fixes #2604, #2599

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=136357364

tli2/guava,EdwardLee03/guava,Xaerxess/guava,berndhopp/guava,rgoldberg/guava,google/guava,Xaerxess/guava,mosoft521/guava,mosoft521/guava,DavesMan/guava,xasx/guava,google/guava,berndhopp/guava,mosoft521/guava,DavesMan/guava,rgoldberg/guava,xasx/guava,tli2/guava,typetools/guava,EdwardLee03/guava,google/guava,typetools/guava