New filter `job_description_contains_not` in Jobs Search endpoint

We've added a new exclusion filter called job_description_contains_not to the Jobs Search endpoint.

This filter helps you exclude jobs that contain specific words in their descriptions. Here's how it works:

• Whole word matching: It only matches complete words using word boundaries, so searching for "quality" won't exclude jobs mentioning "inequality"
• Smart case handling: Searches are case-insensitive by default, but if you use uppercase patterns, we'll respect the exact casing
• Multiple exclusions: You can exclude jobs containing any of several different words at once

Perfect for filtering out roles you're not interested in, like excluding "internship" positions or "remote" jobs when you prefer in-office work.