Fix counter variable name

The counter is referenced in the next section with a different name.

src/content/docs/more-integrations/open-source-telemetry-integrations/opentelemetry/get-started/opentelemetry-tutorial-java.mdx

@@ -633,15 +633,15 @@ Complete the following to add a custom counter:
         private static final AttributeKey<Boolean> ATTR_VALID_N = AttributeKey.booleanKey("fibonacci.valid.n");
 
         private final Tracer tracer;
-        private final LongCounter myCounter;
+        private final LongCounter fibonacciInvocations;
 
         @Autowired
         Controller(OpenTelemetry openTelemetry) {
             // Initialize tracer
             tracer = openTelemetry.getTracer(Controller.class.getName());
             // Initialize instrument
             Meter meter = openTelemetry.getMeter(Controller.class.getName());
-            myCounter = meter
+            fibonacciInvocations = meter
                 .counterBuilder("fibonacci.invocations")
                 .setDescription("Measures the number of times the fibonacci method is invoked.")
                 .build();