[Suggestion, low priority] Add an example that shows how to automatically fill out a given web-formular, via a .pdf file

[rubyFeedback]

Sers gettalong,

This is a low priority suggestion.

I am just about to finish the rewrite of my toolkit-pdf wrapper. I noticed, as I googled, some use
cases of hexapdf I was not quite aware, or at the least not as aware as before. The following
example is pretty neat:

https://hexapdf.gettalong.org/examples/acro_form.html

First, let me say that this is a great idea, to show the working code, with explanations,
and the resulting .pdf file too. For me this is one of the best way to learn; monkey see,
monkey do. Anyway.

As I was searching, I found this example where a user auto-filled in a .pdf formular:

https://tilo-sloboda.medium.com/hexapdf-the-cool-kid-on-the-block-1b8452993866

Could it be considered to add a simple example, onto the examples structure, that
shows the simplest way possible to auto-fill such a .pdf file?

Rationale: I believe this may be useful for people who have to deal with .pdf from
bank/financial transactions or, simpler, from the government. People could then
add some aliases e. g. "autofill with my name"; my_name_is = 'John Doe', and have
that be copied onto the specific entry. (I don't know how simple it is to do so, but
if we need to know the name or ids of the fields, perhaps the example could also
show this, e. g. how to find out the name - I assume hexapdf may have a way
already to show the names, but I am not sure if every user or semi-new user knows
how to access that. Perhaps the example could show this.)

I also have some other suggestions, but I want to keep this simple. (I was not aware
that it is possible to create a web-formula via hexapdf, e. g. drop-down, buttons and
so forth. This is a pretty cool feature; I could probably autogenerate some .pdf files
with custom pre-sets and options, for an elderly relative to use. Anyway that is a
separate suggestion, perhaps I will make such a suggestion but for now, the suggestion
here is just about auto-filling a formular with data.)

[gettalong]

The simplest way to fill out a form is [doc.acro_form.fill](https://hexapdf.gettalong.org/documentation/api/HexaPDF/Type/AcroForm/Form.html#method-i-fill.

I will add an example that shows how to list the form fields and then how to fill it out.

Regarding your other suggestions: It is actually not possible with HexaPDF to create a web form. The example just shows a PDF in the PDF viewer built into the browser (nowadays, the built-in PDF viewers of Firefox and Chrome are quite capable).