Follow-up of https://github.com/zed-industries/zed/pull/26174

* Fixes `./path/foo.bar` not properly parsed as valid open target
* Shows full open target's path in cmd-hover tooltips

Before:

<img width="864" alt="before_1"
src="https://github.com/user-attachments/assets/2575b887-6c4d-486e-8e92-dd76aedf8103"
/>
<img width="864" alt="before_2"
src="https://github.com/user-attachments/assets/ded1f203-523c-4b75-afe9-fe541c785798"
/>

After:

<img width="864" alt="after_1"
src="https://github.com/user-attachments/assets/c50d9ba3-5dfb-4cfb-aed6-00e6fa6f088e"
/>
<img width="864" alt="after_2"
src="https://github.com/user-attachments/assets/0cdc8f34-7faa-4aab-87f3-dc0c8b499842"
/>

Release Notes:



- N/A