refactor: adjust error msg

for 3.0

[TD-16151]

fix(query): fix leastsquares function param type error

docs: fix minor md grammar error

fix(os): win iconv find error

docs: reorganize and refine functions page in 3.0

fix(tmq): auto unsubscribe when consumer close

fix: the role should be OFFLINE after mnode stopped

fix: the max number of mnodes is limited to 3

fix(os): delete two win ctest

feat: tsma refactor

fix: close cause flush result error

fix(query): fix leastsquares column+null and with group by output has empty result

TD-16187

test : add test case for statedurcation and statecount

result

TD-16136

Enh/support tag flt