DOCS-1894 - Improve outlier search operator SEO discoverability

[mafsumo]

Purpose of this pull request

This pull request improves the discoverability of the outlier search operator doc, which was not being surfaced by Google or AI Overview for queries like "outlier sumo logic logs" (traffic was going to the metrics operator doc instead). The word "log"/"logs" previously only appeared deep in example subheadings, never in the title, description, or opening paragraph. This PR:

• Rewrites the frontmatter description to explicitly name Sumo Logic and log data
• Rewrites the opening paragraph to lead with a direct definition naming "Sumo Logic log search results"
• Adds a question-style H2 ("What does the outlier operator do?") for AEO/GEO extraction
• Replaces generic image alt text (e.g. "IIS", "Group b", "Alert") with descriptive alt text for all 7 diagrams

Select the type of change

• Update Content - Revisions, updating sections
• Minor Changes - Typos, formatting, slight revisions
• 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)

https://sumologic.atlassian.net/browse/DOCS-1894

🤖 Generated with Claude Code

[mafsumo]

Planning to hold this for merge until end of month (end of September 2026). Jagadisha V, our log search tech writer, is currently out of office and should review these content/SEO changes before we merge.

Full /seo-audit findings and root-cause analysis are on DOCS-1894.

Separately, we may want a follow-up ticket to apply similar SEO optimizations to other search-operator articles as a wider pass, along with AI-crawling optimizations (AEO/GEO).