chore(cymbal): fix go fixture line comment and assert inline frame source

Author: cat-ph

rust/cymbal/src/core/types/langs/native.rs

@@ -936,6 +936,7 @@ mod test {
         assert_eq!(frames[0].lang, "go");
 
         assert_eq!(frames[1].resolved_name.as_deref(), Some("main.transform"));
+        assert_eq!(frames[1].source.as_deref(), Some("test_go.go"));
         assert_eq!(frames[1].line, Some(16));
         assert_eq!(frames[1].lang, "go");
     }

rust/cymbal/tests/static/native/test_go.go

@@ -14,7 +14,7 @@ func process(value int) int {
 func transform(value int) int {
 	doubled := value * 2
 	doubled += value / 3
-	// Line 17 - this should appear as an inlined frame
+	// Line 16 - this should appear as an inlined frame
 	return doubled + 5
 }