📝 feat(SettingsAnnouncements/SettingsFAQ): update placeholders & success texts, add Markdown/HTML hint
• SettingsAnnouncements.js
– Placeholder now states “Supports Markdown/HTML” for both small & expanded editors
– Success/alert messages unified to use Chinese quotation marks
• SettingsFAQ.js
– Answer textarea placeholder updated with Markdown/HTML support note
– Unified success/alert messages punctuation
These tweaks clarify rich-text support and keep UI copy consistent.
