Add custom roles FF dirs to custom-roles-patterns

What does this MR do and why?

Add custom roles FF dirs to custom-roles-patterns

Adding ee/config/feature_flags/**/custom_ability_*.yml to custom-roles-patterns matcher after we noticed that it was missing causing a broken-master.

• keep lefthook and custom-roles-patterns in sync

related: !208908 (merged)

How to set up and validate locally

Download this patch: diff.patch

git apply diff.patch
git add . && git commit -m "test"
lefthook run pre-push --verbose

Validate you get the following output:

┃  custom_roles_docs ❯

##########
#
# Custom roles documentation is outdated! Please update it by running `bundle exec rake gitlab:custom_roles:compile_docs`.
#
##########

Run the command as recommended:

bundle exec rake gitlab:custom_roles:compile_docs
git add . && git commit -m "test"

Validate that the custom_roles_docs job thingy passes:

lefthook run pre-push --verbose
...
✔️ custom_roles_docs (10.94 seconds)

MR acceptance checklist

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