doc/mruby3.2.md: new file to describe 3.2 changes.

doc/mruby3.2.md

@@ -0,0 +1,27 @@
+# User visible changes in `mruby3.2` from `mruby3.1`
+
+# The language
+
+* Now `a::B = c` should evaluate `a` then `c`.
+* Anonymous arguments `*`, `**`, `&` can be passed for forwarding.
+
+# Tools
+
+## `mruby`
+
+* `-b` only specifies the script is the binary. The files loaded by `-r` are not affected by the option.
+* `mruby` now loads complied binary if the suffix is `.mrb`.
+
+## `mrbc`
+
+* Add `--no-optimize` option to disable optimization.
+
+# mrbgems
+
+## mruby-errno
+
+* `mruby-errno` gem is now bundled.
+
+## mruby-class-ext
+
+* Add `Class#subclasses` method.