Update TODOs

TODO

@@ -1,18 +1,17 @@
 # Bugs
-- stdlib moves line of file, which makes error reporting impossible
 
 # Cleanups
 - Improve error reporting (See ./util/string_util::highlight_position_in_file)
 - Use .peek() instead of .next() for expression parsing
+- stdlib moves line of file, which makes error reporting impossible
 
-# Roadmap
+# Features
-
-## 0.2.0
 - Nested expressions like (1 + (2 * 2))
+- Nested arrays like [[1, 2, 3], [1, 2, 3]]
 - Type inference
 - Multi-file support
-
-## Down the line
 - Argument overloading
+
+# Long term
 - Stable C backend
 - LLVM support

docs/introduction/SUMMARY.md

@@ -4,3 +4,5 @@ Sabre is a bullshit-free (©) programming language that gets out of your way.
 It is meant to "just work", without adding unnecessary and bloated language features.
 
 To get started with Sabre, continue with the [installation](./installation.md)
+
+> **Note**: Some parts have been copied from the [Rust book](https://doc.rust-lang.org/book/).