fix: align pending_connection_errors YARD default with implementation

[sngsmz]

Summary

Fixes an outdated YARD default for :pending_connection_errors on Ferrum::Browser.

Location	Documented default	Actual default
lib/ferrum/browser.rb (before)	false	—
lib/ferrum/browser/options.rb	—	true
docs/2-customization.md	true	true

This PR aligns browser.rb with the implementation and existing docs.

Background

• Add dockerize option, make pending_connection_errors false by default, fix build #561 set :pending_connection_errors default to false
• chore: revert default for :pending_connection_errors to true and update related docs and specs #572 reverted the default to true and updated options.rb and docs/2-customization.md
• lib/ferrum/browser.rb YARD was not updated in chore: revert default for :pending_connection_errors to true and update related docs and specs #572

Test plan

• No code behavior changes
• Verified against options.rb and customization docs

[route]

Thx