docs to Mandarin Chinese (#5960)

docs to Mandarin Chinese (#5960)

* faq_general.md to Chinese

faq_general.md to Chinese
faq finished

* custom_quantum_functions.md to Chinese

custom_quantum_functions.md to Chinese

* custom_quantum_functions.md fix

custom_quantum_functions.md fix

* custom_quantum_functions.md fix translate

custom_quantum_functions.md fix translate

* !ver.English! _summary.md bug fix

 _summary.md bug fix of English doc. add".md" behind "feature_combo"

* !ver.English! custom_quantum_functions.md fix#5869

custom_quantum_functions.md in English : delete redundant "is" . issue#5869

* !ver.English! how_keyboards_work.md link fix

change
https://en.wikipedia.org/wiki/Unicode_input#Hexadecimal_code_input
to
https://en.wikipedia.org/wiki/Unicode_input#Hexadecimal_input
"#Hexadecimal_code_input" not exist

* !English! how_keyboards_work.md add missing "t"

Tied to a specific OS a a time (need recompilation when changing OS);
change to
Tied to a specific OS at a time (need recompilation when changing OS);

* _summary.md improve translation

_summary.md improve translation

* reference_glossary.md into Chinese

reference_glossary.md into Chinese
术语表翻译，这个术语表英文版似乎不太全，应该补充英文版，并在中文版添加其他具有中国特色的术语。