Crashes if file open failed
### Version

moe v0.3.0

Git hash: a86192fd2aa730ce27e03e6ceff49c48eff50b38
Build type: Release

### Environment

_No response_

### Category

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

### Steps to Reproduce

1. `$ touch test.txt`
2. `$ chmod -r test.txt`
3. `$ moe test.txt`

### Detailed Description

/home/fox/git/moe/src/moe.nim(104) moe
/home/fox/git/moe/src/moe.nim(98) main
/home/fox/git/moe/src/moe.nim(85) initEditor
/home/fox/git/moe/src/moe.nim(51) addBufferStatus
/home/fox/.choosenim/toolchains/nim-2.0.0/lib/system/indices.nim(30) []
/home/fox/.choosenim/toolchains/nim-2.0.0/lib/system/fatal.nim(53) sysFatal
Error: unhandled exception: index out of bounds, the container is empty [IndexDefect]