Add clarification on differences of is.convert

[Roang-zero1]

Make it clear that is.convert does not validate the parameters passed to the
created function.
Addresses #12

[Roang-zero1]

In this pull request I've also updated the editorconfig to allow line-breaks in Markdown files (allow trailing white-spaces).
An alternative would be to use \ I would like input on what is preferred.

[wooorm]

Thanks @Roang-zero1 for mentioning this in the docs!

<br>s or whole emphasised sentences are typically not semantic, so I instead opted to rewrite the sentence a bit. Let me know if you don’t feel my wording captures what you intended to write and we can make it clearer!

[Roang-zero1]

LGTM