ci: adds Go 1.19.0-rc.2 into matrix (#714)

This adds the 1.19.0-rc2. in the testing matrix.

This also formats the Godocs across the codebase, as
Go 1.19 has started auto-formatting Godoc. https://github.com/tetratelabs/wazero/issues/426

Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>

runtime.go

@@ -14,6 +14,7 @@ import (
 // Runtime allows embedding of WebAssembly modules.
 //
 // Ex. The below is the basic initialization of wazero's WebAssembly Runtime.
+//
 //	ctx := context.Background()
 //	r := wazero.NewRuntime()
 //	defer r.Close(ctx) // This closes everything this Runtime created.