`CONVERT` works exactly like cast with slightly different syntax:
`CONVERT(<value>, <data_type)` as opposed to `CAST(<value> AS <data_type>)`
Moreover it support format of the MS-SQL data types `SQL_<type>`,
e.g.: `SQL_INTEGER`
Closes: #34513
* New OCTET_LENGTH function
* Changed the way the FunctionRegistry stores functions, considering the alphabetic ordering by name
* Added documentation for the RANDOM function
* Changed the format of the String functions documentation page.
* Adopted the same format for Math functions, but completely changed the examples.
* Added missing documentation for Math functions.
* Added TRUNCATE function, modified ROUND to accept two parameters instead of one. Made the second parameter optional for both functions.
* Added documentation for both functions.
Split function section into multiple chapters
Add String functions
Add (small) section on Conversion/Cast functions
Add missing aggregation functions
Enable documentation testing (was disabled by accident). While at it,
fix failing tests
Improve spec tests to allow multi-line queries (useful for docs)
Add ability to ignore a spec test (name should end with -Ignore)
Marios Trivyzas
Andrei Stefan
Costin Leau
Lisa Cawley