Rename variable for improved readability (#527)

Author: jack-berg

doc-snippets/configuration/src/main/java/otel/SdkMeterProviderConfig.java

@@ -19,7 +19,7 @@ public static SdkMeterProvider create(Resource resource) {
     // builder.registerMetricReader(
     //     MetricReaderConfig.periodicMetricReader(
     //         MetricExporterConfig.otlpHttpMetricExporter("http://localhost:4318/v1/metrics")),
-    //     unusedInstrumentType -> 100);
+    //     instrumentType -> 100);
 
     ViewConfig.dropMetricView(builder, "some.custom.metric");
     ViewConfig.histogramBucketBoundariesView(