[chore] [mdatagen] Fix generation (#12037)

#### Description

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#### Link to tracking issue

#### Testing

I made a PR and none of the CI items failed.

#### Documentation

Signed-off-by: Josh Soref <[email protected]>

Author: jsoref

cmd/mdatagen/internal/samplereceiver/internal/metadata/generated_metrics.go

@@ -23,7 +23,7 @@ import (
 
 {{ range $name, $info := .Attributes }}
 {{- if $info.Enum -}}
-// Attribute{{ $name.Render }} specifies the a value {{ $name }} attribute.
+// Attribute{{ $name.Render }} specifies the value {{ $name }} attribute.
 type Attribute{{ $name.Render }} int
 
 const (