3.x: Fix wrong reference in Single.flattenStreamAsObservable javadoc

[akarnokd]

Fix the copy-paste error of pointing to flattenAsFlowable instead of flattenAsObservable.

[codecov]

Codecov Report

Merging #7206 (d20e9b0) into 3.x (26dddf5) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                3.x    #7206      +/-   ##
============================================
- Coverage     99.57%   99.55%   -0.02%     
  Complexity     6758     6758              
============================================
  Files           747      747              
  Lines         47392    47392              
  Branches       6382     6382              
============================================
- Hits          47189    47180       -9     
- Misses           95       98       +3     
- Partials        108      114       +6     

Impacted Files	Coverage Δ	Complexity Δ
...rc/main/java/io/reactivex/rxjava3/core/Single.java	100.00% <ø> (ø)	196.00 <0.00> (ø)
...l/operators/observable/ObservableFlatMapMaybe.java	92.25% <0.00%> (-5.64%)	2.00% <0.00%> (ø%)
...nternal/operators/observable/ObservableCreate.java	97.43% <0.00%> (-1.71%)	2.00% <0.00%> (ø%)
...ernal/operators/flowable/FlowableFlatMapMaybe.java	96.89% <0.00%> (-1.56%)	2.00% <0.00%> (ø%)
...ternal/operators/completable/CompletableMerge.java	97.29% <0.00%> (-1.36%)	2.00% <0.00%> (ø%)
...a3/internal/operators/flowable/FlowableReplay.java	98.92% <0.00%> (-0.86%)	21.00% <0.00%> (ø%)
.../reactivex/rxjava3/processors/ReplayProcessor.java	99.19% <0.00%> (-0.41%)	52.00% <0.00%> (ø%)
...operators/flowable/FlowableConcatMapScheduler.java	99.20% <0.00%> (-0.40%)	4.00% <0.00%> (ø%)
...3/internal/operators/flowable/FlowableGroupBy.java	84.73% <0.00%> (-0.30%)	3.00% <0.00%> (ø%)
...a/io/reactivex/rxjava3/subjects/ReplaySubject.java	99.37% <0.00%> (-0.21%)	49.00% <0.00%> (ø%)
... and 4 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 26dddf5...38f6efd. Read the comment docs.