Some cleanup of FFI files

Author: headius

lib/prism/ffi.rb

@@ -1,7 +1,14 @@
 # frozen_string_literal: true
 # :markup: markdown
+# --
 # typed: ignore
 
+# This file is responsible for mirroring the API provided by the C extension. There
+# are two backends:
+#
+# * Native FFI based on the 'ffi' gem
+# * WASM compiled to JVM bytecode (JRuby only)
+
 require_relative "ffi/common"
 
 begin

lib/prism/ffi/native_ffi.rb

@@ -1,10 +1,8 @@
 # frozen_string_literal: true
 # :markup: markdown
+# --
 # typed: ignore
 
-# This file is responsible for mirroring the API provided by the C extension by
-# using FFI to call into the shared library.
-
 require "rbconfig"
 require "ffi"
 

lib/prism/ffi/wasm_ffi.rb

@@ -1,10 +1,8 @@
 # frozen_string_literal: true
 # :markup: markdown
+# --
 # typed: ignore
 
-# This file is responsible for mirroring the API provided by the C extension by
-# using FFI to call into the shared library.
-
 require "rbconfig"
 require "ffi"