[Bug] Crash on Viewing GPL-3.0 License File
### Version

moe v0.3.0

Git hash: e4059f17ab837dfe321dd12148617e52e38d8248
Build type: Release


### Environment

OS:  Debian 11
Terminal:  KDE Konsole

### Category

Major — The software does not fulfill the task it is designed for.

### Steps to Reproduce

1. Navigate to any directory containing a GPL-3.0 license (named `LICENSE`, in the following).
2. `moe LICENSE`
3. Scroll down about two screen pages using arrow keys and / or mouse input.
4. Scroll up to the very first line using arrow keys and / or mouse input, again.
5. Crash.

### Detailed Description

The crash information will tell you something about `Invalid parentheses: L [AssertionDefect]`.  This reproducibly refers to line 41 of the GPL-3.0 license which is defined as follows:

```
(1) assert copyright on the software, and (2) offer you this License
```

I assume this bug is related to some tokenisation logic as the crash information refers to the lexical structure of the shown file.