docs: fixed indexes, links and translation

[michelle-qinqin]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  docs

• What is the current behavior? (You can also link to an open issue here)

• What is the new behavior (if this is a feature change)?

• improved the conf.py in zh and en to solve the cross file anchor reference problem
  MyST does not link to anchors within non-auto-generated markdown or HTML files executablebooks/MyST-Parser#564
  https://myst-parser.readthedocs.io/en/latest/faq/index.html?highlight=auto-generated#automatically-create-targets-for-section-headers
  https://myst-parser.readthedocs.io/en/latest/syntax/optional.html#syntax-header-anchors)
• improved the translation about SQL keyword/clause/statement
• fixed the contents of ddl in zh version :there were reduntant "examples"
• fixed the links in en version of select_statement, join , window
• change "boundary description" to "description"
• improved the format of no_table_select as there was a weird number on line 23
• move the overview introduction to the front of some docs