Feature Request: File I/O Exercises in Rustlings

Description

Add a new category (24_file_io/) focused on file operations, a crucial skill for Rust developers currently missing from Rustlings.

Proposed Exercises

1. Basic File Reading (file_io1.rs)

   • Teaches using fs::read_to_string and handling file not found errors
   • Includes input file with text content to read
   • Tests verifying correct content parsing

2. Buffered Reading & Writing (file_io2.rs)

   • Demonstrates efficient reading with BufReader and writing with BufWriter
   • Processes a large input file line by line
   • Writes transformed content to an output file
   • Tests verifying correct transformation

3. Path Manipulation & Metadata (file_io3.rs)

   • Works with Path and PathBuf to handle file paths safely
   • Extracts and manipulates file metadata (creation time, size, permissions)
   • Tests verifying correct metadata extraction

Implementation Structure

• Each exercise includes a Rust file and associated input/output files
• Files are embedded and available during testing
• All exercises follow Rustlings patterns with TODO comments and progressive difficulty

Questions

1. Is handling extra files (inputs/outputs) compatible with current Rustlings structure?
2. Any specific file I/O patterns you'd prefer to prioritize?

I'm happy to draft sample implementations if this proposal is of interest.

cc @mo8it

Start by reading the existing Rustlings exercise structure and how its tests and embedded files are handled. Then assess whether a new 24_file_io/ category can support file_io1.rs, file_io2.rs, file_io3.rs and their input/output files. Done means the structure is agreed and the three progressive exercises have tests for the described file operations.