feat: add more sophisticated formatter selection

[Totto16]

• allow the formatting provider to be set as auto, this means, select the best available one
• add internal priority for formatting providers

This adds an algorithm, that searches for the best available formatter. This results in the following behavior:

• if formatting.provider is set to auto we try to find a formatter in the following order ["meson", "muon"], if one of them is found in this order, that one is used

• if formatting.provider is set to a specific formatter, it only tries that one and fails, if it didn't find that one

fixes #274

Let me know, me if this solution is acceptable. The problem with the previous code is, that it wasn't really designed to handle multiple formatting providers that well.

[tristan957]

• allow the formatting provider to be set as null, this means, select the best available one

  • add internal priority for formatting providers

Instead of null, can we use "auto"?

This adds an algorithm, that searches for the best available formatter. This results in the following behavior:

* if `formatting.provider` is set to `null` we try to find a formatter in the following order `["meson", "muon"`], if one of them is found in this order, that one is used

* if `formatting.provider` is set to `"meson"` we try to find a formatter in the following order `["meson", "muon"`], even if we set the provider to be `"meson"` and meson is not found, muon is used

This behavior doesn't make much sense to me. If the user requests meson, they should get meson if available, else don't format.

* The same for muon, it is a priority if the user selected it, but meson might be used, if muon is not found

The only problem I can see, if you want to disable the formatter, there is no way of doing that, but that was previously also not the case.

fixes #274

Let me know, me if this solution is acceptable. The problem with the previous code is, that it wasn't really designed to handle multiple formatting providers that well.

Let me know your thoughts!

[Totto16]

• allow the formatting provider to be set as null, this means, select the best available one

  • add internal priority for formatting providers

Instead of null, can we use "auto"?

Yes that is also a good idea 👍🏼

This adds an algorithm, that searches for the best available formatter. This results in the following behavior:

* if `formatting.provider` is set to `null` we try to find a formatter in the following order `["meson", "muon"`], if one of them is found in this order, that one is used

* if `formatting.provider` is set to `"meson"` we try to find a formatter in the following order `["meson", "muon"`], even if we set the provider to be `"meson"` and meson is not found, muon is used

This behavior doesn't make much sense to me. If the user requests meson, they should get meson if available, else don't format.

Ok, So I'll change it, to just do that on the "auto" value 👍🏼

* The same for muon, it is a priority if the user selected it, but meson might be used, if muon is not found

The only problem I can see, if you want to disable the formatter, there is no way of doing that, but that was previously also not the case.
fixes #274
Let me know, me if this solution is acceptable. The problem with the previous code is, that it wasn't really designed to handle multiple formatting providers that well.

Let me know your thoughts!

[tristan957]

Thanks for your contributions to the extension. I'll try and a get a release out after this PR merges.

[Totto16]

I implemented the suggested changes 😄