DOCS-680 - Update role filtering guidance on "role stacking"

[jpipkin1]

Purpose of this pull request

This pull request updates these articles:

• https://help.sumologic.com/docs/manage/users-roles/roles/create-manage-roles/
• https://help.sumologic.com/docs/manage/users-roles/roles/construct-search-filter-for-role/
• https://help.sumologic.com/docs/manage/users-roles/users/create-edit-users/

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)

DOCS-680

[jpipkin1]

@manashar4, could you review this PR?

[JV0812]

LGTM

[kimsauce]

This looks good to me! I suggested a few minor edits for clarity and brevity, but the original is solid. 👍

[jpipkin1]

Great suggestions, @kimsauce! Thank you.

Requested updates are complete.