1. feat(search_multi): add setting option META_FIELD
2. feat(search_multi): add treeExplain for GrammarPresenter
3. feat(search_multi): add qualifiers footnoteref, footnote, footnotename, footnotecontent, alert, alertname and alertcontent
4. feat(window_tab): add experimental feature ENFORCE_SINGLETON (#947)
5. fix(window_tab): restore MountFolder after switching other repository (#1256)
6. fix(static_markers): style error occurred when enabled after initialization
7. improve(search_multi): improve qualifiers highlight, task, taskdone and tasktodo
8. i18n: improve i18n
9. chore: update test cases
10. doc: update README.md and README-cn.md