Update sa few pages with proper people ops terms
Update source/handbook/product/index.html.md, source/handbook/sales-onboarding/index.html.md, source/handbook/security/index.html.md, source/handbook/spending-company-money/index.html.md, source/handbook/stock-options/index.html.md, source/handbook/tax/index.html.md, source/handbook/tools-and-tips/index.html.md, source/handbook/underperformance/index.html.md files