Bug Report

When using tsgo to generate declaration source mapping files, the source mappings incorrectly point to the declaration file (.d.ts) instead of the original source file (.ts/.tsx).

Expected Behavior

The source map should point to the original source TypeScript file, allowing proper navigation from the declaration file to the source code.

Actual Behavior

The source map points to the declaration file itself, making source navigation ineffective.

Reproduction

1. Generate declaration files with source maps using tsgo
2. Check the sources field in the generated .d.ts.map file
3. Observe that it points to the .d.ts file instead of the original .ts file