Correct some syntax/compilation errors in Titanic Binary Classification Docs Example

[crupley]

Related issues
#201

Describe the proposed solution
Corrections to the errors

Describe alternatives you've considered
None

Additional context
None

[salesforce-cla]

Thanks for the contribution! It looks like @crupley is an internal user so signing the CLA is not required. However, we need to confirm this.

[codecov]

Codecov Report

Merging #202 into master will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #202      +/-   ##
==========================================
- Coverage    86.4%   86.35%   -0.05%     
==========================================
  Files         309      309              
  Lines       10009    10009              
  Branches      351      557     +206     
==========================================
- Hits         8648     8643       -5     
- Misses       1361     1366       +5

Impacted Files	Coverage Δ
.../salesforce/op/features/FeatureBuilderMacros.scala	0% <0%> (-100%)	⬇️
...es/src/main/scala/com/salesforce/op/OpParams.scala	85.71% <0%> (-4.09%)	⬇️

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