fix: improve component attrs section

[kazupon]

Description of Problem

The documentation says that $attrs can be accessed by setting inheritAttrs: false.
However, $attrs can be accessed with or without inheritAttrs setting.

The rfcs says the following:

this.$attrs (and context.attrs for setup() and functional components) now contains all attributes passed to the component (as long as it is not declared as props).

https://github.com/vuejs/rfcs/blob/master/active-rfcs/0031-attr-fallthrough.md#inheritattrs-false

Proposed Solution

Remove the following sentence and add the new sentence of this PR, or we change to another explanation.

Additional Information

I hope that you update my docs is wrote with my poor English! 🙇

[NataliaTepluhina]

@kazupon thank you for the fix! Looks perfect to me 👍🏻