Update changelog with a few fixes.
# Changelog
All notable changes to this project will be documented in this file.
+## Unreleased - ???
+- Fix printing issue in `doc` macro.
+- Numerous updates to function docstrings
+- Add `defdyn` aliases for various dynamic bindings used in core.
+- Install `janet.h` symlink to make Janet native libraries and applications
+ easier to build without `jpm`.
+
## 1.21.2 - 2022-04-01
- C functions `janet_dobytes` and `janet_dostring` will now enter the event loop if it is enabled.
- Fix hashing regression - hash of negative 0 must be the same as positive 0 since they are equal.
