Fix describe -d for lazy records (#10836)

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# Description
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This PR fixes an overlook from a previous PR. It now correctly returns
the details on lazy records.

# User-Facing Changes
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helps us keep track of breaking changes. -->
Describe detailed now returns the expected result.

crates/nu-cmd-lang/src/core_commands/describe.rs

@@ -397,6 +397,7 @@ fn describe_value(
                             describe_value(val.vals[i].clone(), head, engine_state, call)?,
                         );
                     }
+                    record.push("columns", Value::record(record_cols, head));
                 } else {
                     let cols = val.column_names();
                     record.push("length", Value::int(cols.len() as i64, head));
@@ -406,7 +407,7 @@ fn describe_value(
                 record.push("length", Value::int(cols.len() as i64, head));
             }
 
-            Value::record(record!(), head)
+            Value::record(record, head)
         }
     })
 }