Few rephrasing changes.

Spelling, syntax

Rephrasing and grammar

Rephrases some sentences.

rephrased sentences

Rephrased 2 sentences for readability.

Rephrased sentence.

Rephrased sentences.

Update 07-function.md

modify the inconsistent argument name

List was not formatted correctly in FAQ

Rephrasing and spelling

Rephrased sentences, some stylistic changes.

Stylistics, grammar and changed string "topic" to "topicname" in one Java example code snippet since topic is a keyword in TDengine.

ci: add 2.6 branch to ci

[TS-1568]

Stylistic changes.

rephrased slightly

Spelling, grammar and stylistic.

Stylistic and grammar changes.

Rephrased sentences.

Rephrasing in some places.