IBX-7565: Document how to limit content types in udw when creating new page builder blocks

[vidarl]

Question	Answer
JIRA Ticket	IBX-7565
Versions	3.3, 4.5
Edition	Experience

At the moment, I know about the following issues:

• I am unsure if this should be documented on this page, or somewhere else
• All links are absolute
  • Those can be made relative once you have decided on location where this should be placed
• All code are inline, not in separate files. Can also be fixed once location has been decided
• The differences between how do customize embed vs locationlist are minimal. Maybe remove doc for locationlist ?
• The are some changes in classnames,filenames, namespaces etc when merging to 4.5 ....

Checklist

• Text renders correctly
• Text has been checked with vale
• Description metadata is up to date
• Redirects cover removed/moved pages
• Code samples are working
• PHP code samples have been fixed with PHP CS fixer
• Added link to this PR in relevant JIRA ticket or code PR

[adriendupuis]

I'll merge this in "Create custom block". I'll start with 4.x and downgrade it to 3.3 latter.

I see two topics:

• Custom UDW: IBX-7565: Custom block's UDW config (4.x) #2331
• Pre-render event that is documented in "Page blocks" (latest) (3.3) which could be betterly illustrated in "Create custom block": Add a pre-render subscriber to custom block (4.x) #2332

[adriendupuis]

Downgrades back to 3.3:

• IBX-7565: Custom block's UDW config (3.3) #2351
• Add a pre-render subscriber to custom block (3.3) #2352

[adriendupuis]

Covered by other PRs