Add the enclosing interface references to remove javadoc errors

[jkwatson]

resolves #900

[codecov-io]

Codecov Report

Merging #902 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #902      +/-   ##
============================================
- Coverage     82.65%   82.61%   -0.04%     
  Complexity      835      835              
============================================
  Files           111      111              
  Lines          2934     2934              
  Branches        251      251              
============================================
- Hits           2425     2424       -1     
  Misses          397      397              
- Partials        112      113       +1

Impacted Files	Coverage Δ	Complexity Δ
...io/opentelemetry/sdk/metrics/DoubleCounterSdk.java	95.83% <ø> (ø)	5 <0> (ø)	⬇️
...a/io/opentelemetry/sdk/metrics/LongMeasureSdk.java	75% <ø> (ø)	5 <0> (ø)	⬇️
...io/opentelemetry/sdk/metrics/DoubleMeasureSdk.java	75% <ø> (ø)	5 <0> (ø)	⬇️
...a/io/opentelemetry/sdk/metrics/LongCounterSdk.java	95.83% <ø> (ø)	5 <0> (ø)	⬇️
...elemetry/sdk/trace/export/BatchSpansProcessor.java	89.76% <0%> (-0.79%)	7% <0%> (ø)

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