Autocomplete 'vi' in the middle of the title

Keep all the posts in the same directory. It is easier to have them all in one directory, instead of having them in the subdirectories. To edit it easily, you can use vi with bash autocomplete:

Instead of:

```vi 2020-12-23-something.md```

, you will be able to use:

```vi something<TAB>```

Add following into ~/.bashrc:

```
# autocomplete vi

_vi_middle_of_file_completion() {
  mapfile -t COMPREPLY < <( find . -maxdepth 1 -type f | grep --color=never -i "${COMP_WORDS[COMP_CWORD]}" )
}
complete -o nospace -F _vi_middle_of_file_completion vi
```