[General] Implement horizontal scrolling and word wrap in "File changed" view for PRs.

**Mood:** 😊
**Category:** General

Implement horizontal scrolling and word wrap in "File changed" view for PRs. Currently, long lines flow over the edge of the screen and I can't scroll horizontally and there's no word wrap option. Eg in the below screenshot, the edit is wide and there's no way to scroll.


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| Field | Value |
| --- | --- |
| App version | 0.2.2 |
| OS | Windows 10.0.26200 |
| Theme | GitHub |
| Path | / |
| Tenure | Week 6 |

先找到桌面應用程式中用於 pull request 的「File changed」檢視畫面，並在 Windows 上使用長行重現溢位問題。檢查該檢視畫面目前如何處理寬內容，接著驗證使用者可以水平捲動並啟用自動換行，而不會讓文字溢出畫面。

由索引模型根據 Issue 內容生成。