rustlings/exercises/error_handling/README.md

For this exercise check out the sections:
- [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html) 
- [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html) 

of the Rust Book.
Changed Rust Book versions in links to 2018 Forgot to add changes to last commit. 2018-11-27 09:54:01 +00:00			`For this exercise check out the sections:`
Fix links by deleting book version 2019-04-08 21:02:04 +01:00			`- [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html)`
			`- [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html)`
Created sub READMEs for CLI only version Sub READMEs contain the relevant resources from the main README of the web version. All second edition Rust Book links were updated to the 2018 edition. Fixed to typos in main README.md. 2018-11-26 15:43:42 +00:00
Fix links by deleting book version 2019-04-08 21:02:04 +01:00			`of the Rust Book.`