[Suggestion] Correct 'Organizing Data Access' documentation page

[Andrei Iakovlev]

This page https://www.mql5.com/en/docs/series/timeseries_access says:

"The CheckLoadHistory() function is designed as a universal function that can be called from any program (Expert Advisor, script or indicator)".

Which can't be right, because CheckLoadHistory() function uses Sleep() function, which doesn't work in indicators.

Please correct this part of that page, or (better way), also include an example of an indicator with CheckLoadHistory() function.

[Andrei Iakovlev]

Another mistake is in this text: "If the start date first_server_date of the server is lower than the start date first_date of the symbol".

Insted of lower should be greater.

if(first_date>0 && first_date<first_server_date)

And a small mistake is here: "If the attempt fails, then value of the copied will be equal to null".

If the attempt fails, then value of the copied will be equal to -1, won't it?