Modernize (#7089)

Use
https://pkg.go.dev/golang.org/x/tools/gopls/internal/analysis/modernize
to update code to new style.

---------

Co-authored-by: Flc゛ <four_leaf_clover@foxmail.com>
Co-authored-by: Damien Mathieu <42@dmathieu.com>

sdk/trace/tracetest/span.go

@@ -37,7 +37,7 @@ func (s SpanStubs) Snapshots() []tracesdk.ReadOnlySpan {
 	}
 
 	ro := make([]tracesdk.ReadOnlySpan, len(s))
-	for i := 0; i < len(s); i++ {
+	for i := range s {
 		ro[i] = s[i].Snapshot()
 	}
 	return ro