improve error message regarding JP2K content kind

[cconcolato]

issue #200

[codecov]

Codecov Report

Merging #248 into master will increase coverage by 0.03%.
The diff coverage is 86.36%.

@@             Coverage Diff              @@
##             master     #248      +/-   ##
============================================
+ Coverage     66.82%   66.86%   +0.03%     
- Complexity     1482     1488       +6     
============================================
  Files           153      154       +1     
  Lines         10740    10758      +18     
  Branches       1590     1591       +1     
============================================
+ Hits           7177     7193      +16     
- Misses         2794     2795       +1     
- Partials        769      770       +1

Impacted Files	Coverage Δ	Complexity Δ
...x/imflibrary/st2067_2/Application2Composition.java	88.43% <75%> (ø)	35 <0> (ø)	⬇️
...com/netflix/imflibrary/st0422/JP2KContentKind.java	88.88% <88.88%> (ø)	6 <6> (?)

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[MarcAntoine-Arnaud]

LGTM