Add the ability to import external code files #226
Description
Instead of writing code in a code block:
```c
// some code
```I'd like to be able to write something like
```c from:/path/to/file.c
```{{ message }}
Instead of writing code in a code block:
```c
// some code
```I'd like to be able to write something like
```c from:/path/to/file.c
```