`mrb_int` may not fit in `fixnum` (inline integer).

Instead, copy them from the outer frame as CRuby does.

build(deps): bump actions/checkout from 2 to 2.3.4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 2.3.4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2...v2.3.4)
Signed-off-by: dependabot[bot] <support@github.com>

The performance of `Enumerable#entries` are significantly slower than
`Array#to_a`.

Except for compatibility code.

- `puts` behavior changed as CRuby
- fix wrong behavior in re-raising in `rescue`

`gettimeofday` emulation needed no longer.

Extend the tab with 8 whitespace

Order the EditorConfig properties

`Symbol#name` is similar to `#to_s` but returns a frozen string.

This work was done as follows:
- check:   `git grep $'\011' -- :^oss-fuzz`
- convert: `ruby -pi -e 'nil while $_.sub!(/^(.*?)\t/) { $1 + " " * (8 - $1.size % 8) }'`

The `doc/guide/{compile,mrbgems}.md` file adds and removes whitespace to make the directory tree look the same.
In `mrbgems/mruby-socket/src/socket.c`, there is a part where the indent is changed from 4 to 2 at the same time as the tab is changed.

build(deps): bump github/super-linter from v3 to v3.17.0

Bumps [github/super-linter](https://github.com/github/super-linter) from v3 to v3.17.0.
- [Release notes](https://github.com/github/super-linter/releases)
- [Commits](https://github.com/github/super-linter/compare/v3...28cfebb84fd6dd9e8773b5efe5ac0f8f3714f228)
Signed-off-by: dependabot[bot] <support@github.com>

Fix documents for `mruby-io`

Update gem spec for `mruby-sleep`

Fix whitespace in `src/symbol.c`

To align the spec like any other core mrbgems:
- Delete `spec.version`
- Set `spec.summary`

In the ancient Ruby, symbols are represented by integers. In that era,
to get string representation from integers, we used `Integer#id2sym`
method. Later, `Symbol` was introduced, and `id2sym` was used for
compatibility. Today, no one uses `id2sym` any longer. It is described
in ISO 30170:2012 standard but I consider it as a mistake.

Enclose the table contents of `opcode.md` as code

As CRuby behaves.

Fix typo in `mrbgems/mruby-io/mrblib/io.rb`; ref cb55e7ec

When the receiver is the instance of subclass of `String`.

- `String#each_char`
- `String#each_line`
- `String#partition`

It used to be an alias to `IO#each_byte` but those methods should have
behave differently.

Even called for subclass of `Array`, according to new Ruby3.0 behavior.
Other methods of `Array` behave as Ruby3.0 from the first hand.