Minor changes for kotlinization

[jarekratajski]

1. internal classes actually made internal
2. removed var mutation

[codecov]

Codecov Report

Merging #26 into master will decrease coverage by 1.73%.
The diff coverage is 76.00%.

@@             Coverage Diff              @@
##             master      #26      +/-   ##
============================================
- Coverage     88.60%   86.87%   -1.74%     
  Complexity       81       81              
============================================
  Files             4        4              
  Lines           158      160       +2     
  Branches         30       30              
============================================
- Hits            140      139       -1     
- Misses            1        4       +3     
  Partials         17       17              

Impacted Files	Coverage Δ	Complexity Δ
...omintrospectiongenerator/internal/GeneratorImpl.kt	82.20% <57.14%> (-2.28%)	71.00 <1.00> (ø)
...chemafromintrospectiongenerator/internal/Schema.kt	100.00% <100.00%> (ø)	6.00 <1.00> (ø)

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[mstachniuk]

Thank you for the PR. Generally, I like all the changes, outside this one (the repeated else { "" } block. Maybe StringBuilder will be better here?

[jarekratajski]

That was more an example how to do that without variables using if expression.
Actually (actually) it also showed no tests for else branch.
But - yes surely there should be a better way to write this part of code...

[jarekratajski]

But as for StringBuilder I am not allowed to use StringBuilder directly :-)