Merge branch '13679-fix' into 'master'

Adjust documentation of permissions

## What does this MR do?
This MR improves the documentation of the permissions by mentioning that internal projects do not enforce the Guest role.
## Are there points in the code the reviewer needs to double check?
No code was touched - only the documentation was adjusted.
## Why was this MR needed?
Without this adjustment it might not be clear how you can set up an internal project to be pullable by everyone whilst having the issue tracker and labels managed by permitted people only.
## What are the relevant issue numbers?
#13679 

See merge request !2925

CHANGELOG

@@ -4,6 +4,7 @@ v 8.6.0 (unreleased)
   - Improve the formatting for the user page bio (Connor Shea)
   - Fix avatar stretching by providing a cropping feature (Johann Pardanaud)
   - Strip leading and trailing spaces in URL validator (evuez)
+  - Update documentation to reflect Guest role not being enforced on internal projects
 
 v 8.5.1
   - Fix group projects styles

doc/permissions/permissions.md

@@ -6,7 +6,7 @@ If a user is both in a project group and in the project itself, the highest perm
 
 If a user is a GitLab administrator they receive all permissions.
 
-On public projects the Guest role is not enforced.
+On public and internal projects the Guest role is not enforced.
 All users will be able to create issues, leave comments, and pull or download the project code.
 
 To add or import a user, you can follow the [project users and members