* Replace underscores with hyphens

* remove temporary code

* fix style check

* fix collapse

* CLICKHOUSE-4063: less manual html @ index.md

* CLICKHOUSE-4063: recommend markdown="1" in README.md

* CLICKHOUSE-4003: manually purge custom.css for now

* CLICKHOUSE-4064: expand <details> before any print (including to pdf)

* CLICKHOUSE-3927: rearrange interfaces/formats.md a bit

* CLICKHOUSE-3306: add few http headers

* Remove copy-paste introduced in #3392

* Hopefully better chinese fonts #3392

* get rid of tabs @ custom.css

* Apply comments and patch from #3384

* Add jdbc.md to ToC and some translation, though it still looks badly incomplete

* minor punctuation

* Add some backlinks to official website from mirrors that just blindly take markdown sources

* Do not make fonts extra light

* find . -name '*.md' -type f | xargs -I{} perl -pi -e 's//g' {}

* find . -name '*.md' -type f | xargs -I{} perl -pi -e 's/ sql/g' {}

* Remove outdated stuff from roadmap.md

* Not so light font on front page too

* Refactor Chinese formats.md to match recent changes in other languages

* Additional .gitignore entries

* Merge a bunch of small articles about system tables into single one

* Merge a bunch of small articles about formats into single one

* Adapt table with formats to English docs too

* Add SPb meetup link to main page

* Move Utilities out of top level of docs (the location is probably not yet final) + translate couple articles

* Merge MacOS.md into build_osx.md

* Move Data types higher in ToC

* Publish changelog on website alongside documentation

* Few fixes for en/table_engines/file.md

* Use smaller header sizes in changelogs

* Group up table engines inside ToC

* Move table engines out of top level too

* Specificy in ToC that query language is SQL based. Thats a bit excessive, but catches eye.

* Move stuff that is part of query language into respective folder

* Move table functions lower in ToC

* Lost redirects.txt update

* Do not rely on comments in yaml + fix few ru titles

* Extract major parts of queries.md into separate articles

* queries.md has been supposed to be removed

* Fix weird translation

* Fix a bunch of links

* There is only table of contents left

* "Query language" is actually part of SQL abbreviation

* Change filename in README.md too

* fix mistype

Edit page link is fixed too for both language versions of documentation.