[docs] Fix RecordAndSample typo (open-telemetry#5870)

Co-authored-by: Mikel Blanchard <[email protected]>

docs/trace/extending-the-sdk/README.md

@@ -338,7 +338,7 @@ class MySampler : Sampler
 {
     public override SamplingResult ShouldSample(in SamplingParameters samplingParameters)
     {
-        return new SamplingResult(SamplingDecision.RecordAndSampled);
+        return new SamplingResult(SamplingDecision.RecordAndSample);
     }
 }
 ```