DOCS-1605 - Add frontmatter descriptions to parse operators

[JV0812]

Purpose of this pull request

This pull request adds comprehensive SEO-friendly frontmatter descriptions to all 9 parse operator documentation files. These descriptions improve search discoverability and provide clear summaries of parsing capabilities for different log formats.

Summary of Changes:

• Added description: field to frontmatter of 9 parse operator docs
• Each description is 49-65 words following Sumo Logic style guidelines
• Descriptions include parsing methods, format support, and practical use cases
• Keywords optimized for SEO and search discoverability

Before: Files had no frontmatter descriptions
After: All files have concise, format-specific descriptions

Example additions:

• parse-csv-formatted-logs.md: "Use the parse operator to extract fields from CSV-formatted log entries..."
• parse-keyvalue-formatted-logs.md: "Use the keyvalue parse operator to extract key-value pairs from log messages..."
• parsedate.md: "Use the parseDate operator to parse date and time strings from log entries..."

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)

https://sumologic.atlassian.net/browse/DOCS-1605

[kimsauce]

Thanks for adding these, Jagadisha! One issue to address:

Descriptions are too long (critical)

All 9 descriptions are 311–372 characters. The hard limit for Google to display a full meta description is 160 characters — anything over that gets truncated mid-sentence in search results, which defeats the purpose of adding them. Ideal range is 140–160 characters.

Each description should be trimmed to the first 1–2 sentences that capture what the operator does, cutting the "Useful for..." and "Ideal for..." trailing sentences.