2.x: Fix wrong comments in Functions.java “Function3” -> “BiFunction”

[ggikko]

I'm using this library in my company(KakaoBank in Korea) and interested in this library.. so I read whole code these days. I feel really thanks for all people who make awesome library and I just wanted to contribute this library.

[codecov]

Codecov Report

Merging #5230 into 2.x will decrease coverage by <.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                2.x    #5230      +/-   ##
============================================
- Coverage     96.02%   96.01%   -0.01%     
- Complexity     5745     5752       +7     
============================================
  Files           628      628              
  Lines         41074    41074              
  Branches       5697     5697              
============================================
- Hits          39443    39439       -4     
+ Misses          655      651       -4     
- Partials        976      984       +8

Impacted Files	Coverage Δ	Complexity Δ
...ava/io/reactivex/internal/functions/Functions.java	99.11% <ø> (ø)	35 <0> (ø)	⬇️
...ernal/operators/flowable/FlowableFlatMapMaybe.java	91.54% <0%> (-6.47%)	2% <0%> (ø)
.../operators/completable/CompletableConcatArray.java	93.75% <0%> (-6.25%)	2% <0%> (ø)
.../internal/operators/maybe/MaybeTakeUntilMaybe.java	93.87% <0%> (-6.13%)	2% <0%> (ø)
...main/java/io/reactivex/subjects/SingleSubject.java	95.23% <0%> (-4.77%)	38% <0%> (-2%)
...rnal/subscriptions/DeferredScalarSubscription.java	93.84% <0%> (-4.62%)	27% <0%> (-1%)
...ernal/operators/maybe/MaybeTakeUntilPublisher.java	96% <0%> (-4%)	2% <0%> (ø)
...l/operators/observable/ObservableFlatMapMaybe.java	91.5% <0%> (-3.93%)	2% <0%> (ø)
...ors/observable/ObservableSampleWithObservable.java	93.97% <0%> (-3.62%)	3% <0%> (ø)
...ternal/operators/observable/ObservablePublish.java	92.1% <0%> (-3.51%)	10% <0%> (ø)
... and 35 more

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[ggikko]

I also added fail test case toFunction about Functions.java

[akarnokd]

Actually, BiFunction, Function3..Function9 would be better.

[ggikko]

I agree.

[akarnokd]

Please add @SuppressWarnings({"unchecked", "rawtypes"}) to all these new methods.

[ggikko]

Thank you for comment.