Mun v0.2.1

This patch release for Mun v0.2.0 includes a variety of bug fixes:

^_🔗 fix

• Remove return-blocking semicolon from ch01 listing 01 of the book

^_🔗 fix

• Code blocks in ch02-02-functions of the book

^_🔗 fix

• Replace overly complicated redirection rules with a simple hack

^_🔗 fix

• Missing argument for fibonacci function in the book

^_🔗 refactor

• Type-safe inkwell types

^_🔗 fix

• Replace float with f32 in the book

^_🔗 fix

• Windows libclang issues

^_🔗 fix

• Rust v1.44 cargo fmt and clippy errors

^_🔗 fix

• Crash on missing nested private function

^_🔗 fix

• Panic when using mun build

^_🔗 fix

• clippy::many_single_char_names in macro

^_🔗 fix

• Compiler panics when accessing a field of a temporary

^_🔗 fix

• LLVM assertions

^_🔗 fix

• Proper tarpaulin skip attribute

Special thanks to @RadicalZephyr, @benediktwerner, and @fominok for their contributions to this release; and to @jDomantas and @sigmaSd for the initial discovery and reporting of fixed issues.