Remove MJIT's private constants from docs [ci skip]

lib/ruby_vm/mjit/c_pointer.rb

@@ -1,4 +1,4 @@
-module RubyVM::MJIT
+module RubyVM::MJIT # :nodoc: all
   # Every class under this namespace is a pointer. Even if the type is
   # immediate, it shouldn't be dereferenced until `*` is called.
   module CPointer

lib/ruby_vm/mjit/c_type.rb

@@ -2,7 +2,7 @@ require 'fiddle'
 require 'fiddle/pack'
 require_relative 'c_pointer'
 
-module RubyVM::MJIT
+module RubyVM::MJIT # :nodoc: all
   module CType
     module Struct
       # @param name [String]

lib/ruby_vm/mjit/compiler.rb

@@ -13,7 +13,7 @@
 #   DISPATCH_ORIGINAL_INSN(): expanded in _mjit_compile_insn.erb
 #   THROW_EXCEPTION(): specially defined for JIT
 #   RESTORE_REGS(): specially defined for `leave`
-class RubyVM::MJIT::Compiler
+class RubyVM::MJIT::Compiler # :nodoc: all
   C = RubyVM::MJIT.const_get(:C, false)
   INSNS = RubyVM::MJIT.const_get(:INSNS, false)
   UNSUPPORTED_INSNS = [