Update handbook guide for updating to D9 to be generalized for D10 and future major updates

This page is in the guide How to prepare your Drupal 7 or 8 site for Drupal 9 which is .. odd.

There is also this page which seems to be doing the same thing, Upgrading from Drupal 8 to Drupal 9 (or later)

I was going to make some suggestions to unify these pages but I just ran out of steam.

Right now we have this structure, abbreviate of course. The 'Upgrading Drupal' section is primarily migrate related except for the ** page.

Drupal
  Installing Drupal
  Updating Drupal
  Upgrading Drupal  
    How to prepare your Drupal 7 or 8 site for Drupal 9
      Upgrading a Drupal 8 site to Drupal 9 **

We could rename 'Updating Drupal' to Updating Drupal 8+' and rename 'Upgrading Drupal' 'Updating from Drupal 6 or Drupal 7 to Drupal 8+' and move the '**' page to the 'Updating Drupal 8+' section. I think that will guide people to the information they need and not mix the two up.

Drupal
  Installing Drupal
  Update Drupal8+
       Move the sections from Updating Drupal here
       Move "Upgrading a Drupal 8 site to Drupal 9 **" here
  Updating Drupal 7 or earlier to Drupal 8+
        Move the sections from Upgrading Drupal here.
      

Historically we used updating to mean updating within the same major while upgrading meant moving up a major or two. Are we now to use updating regardless of versions? I think that is one thing we need to agree on to make sure we structure it in a forward looking way.

The Upgrading Drupal guide contains guides for upgrading from D6/D7 and from D8, D9. The two should be separated.

Change this

Drupal
  - Understanding Drupal
  - System Requirements
  - Installing Drupal
  - Updating Drupal
 ...
  - Multilingual Guide
  - Upgrading Drupal
  --- Preparing your site to upgrade to a newer major version     *** Similar title 1, repeating content?
  ----- Deprecation checking and correction tools to prepare for a new Drupal major version
  ----- Prepare a Drupal 7 site for Drupal 9                                   *** Similar title 1, repeating content?
  ----- Preparing Drupal.org projects for Drupal 9
  ----- Preparing for use of Twig 2 in Drupal 9
  ----- Upgrading a Drupal 8 site to Drupal 9                                *** Similar title 2, repeating content?
  --- Upgrading from Drupal 6 or 7 to Drupal 9 (or later)
  --- Upgrading from Drupal 8 (or later) to a newer major version   *** Similar title 2, repeating content?
  --- Preparing a site for upgrade to Drupal 9                                   *** Similar title 1, repeating content?
  --- Learn key Drupal 8 (or later) concepts prior to upgrading
  ---  then many guides about Migrate

To

Drupal
  - Understanding Drupal
  - System Requirements
  - Installing Drupal
  - Updating Drupal
 ...
  - Multilingual Guide
  - Upgrading Drupal
 --- Learn key Drupal 8 (or later) concepts prior to upgrading
  --- Upgrade from D8 or later
  ------ Preparing your site to upgrade to a newer major version
  ------ Upgrading from Drupal 8 (or later) to a newer major version
  ------ Upgrading a Drupal 8 site to Drupal 9   
  --- Upgrade from D6/D7
  ------ Preparing your D6/D7 site to upgrade to a newer major version
  ------ Upgrading from Drupal 6 or 7 to Drupal 9 (or later)
  ------  then many guides about Migrate

Personally, I like the distinction of upgrade/update as stated in #5 but I don't mind it that changes. I am far more concerned that the structure of the documentation here is unhelpful.

I've done a bit of re-ordering at Upgrading Drupal and made new page for 'Upgrading from Drupal 9 to Drupal 10'. I thought a new page was needed so that there is place to mention things to watch out for that are unique to Drupal 9 to 10. The new page uses the Overview from Upgrading from Drupal 8 to Drupal 9 as a start. It definitely needs links to the correct composer instructions.

That doesn't meet the goal in the IS of having a generic page but maybe that is OK?

The new structure is:

Upgrading from Drupal 8 (or later)
-- Upgrading from Drupal 8 to Drupal 9
-- Upgrading from Drupal 9 to Drupal 10

Added generic instructions.

And the guides "Upgrading Drupal" and "Updating Drupal" are now next to each other on the Drupal wiki. I am hoping that will help the readers. I think eojthebrave did that. Thanks!

The pages are ready for review.

Reviewing the pages and they look fine to me. D10 being out a few months if they were really bad think someone would of said something by now.

Though I think it may be worth adding something for taking over abandoned modules. People are quickly realizing that modules they use are abandoned or lacking support.

The "Plan" category is used for meta issues that capture process and give an overview to problems that cannot be solved with one issue.

Therefor, I am changing back to a task.

The suggestion in #10 is a change of scope. This issue is specifically about generalizing a set of pages, not adding more data. Changing back to NR.

I'll talk to @smustgrave in #needs-review-queue about the suggestion in #10.

@quietone did bring it up and I was coming at it with more of a developer mindset so needing the ability to take over a module and update the code for D10 would be out of the realm of an upgrader.

This all looks fine to me, marking fixed. Wonder if it should have been against https://www.drupal.org/project/issues/documentation