Various docs updates

[bkamins]

Fixes #1265

• makes obsolete Construction from a named tuple documentation #1580 (I put the example in the better place in the manual) and Add docstrings for names, size, and order #1814 (I have added documentation to more of related functions).

[bkamins]

❌ is due to coverage

[nalimilan]

Suggested change

	Here we present two ways that this can be achieved, one using `Tables.rowtable`
	Here we present two ways that this can be achieved, one using the `Tables.rowtable`

But I'd just stop after "achieved", as the test of the sentence merely repeats the code. :-)

Finally, isn't the first way much faster? In that case maybe not recommend the second one?

[bkamins]

The first way is only 50% faster (which was a surprise to me), but it is consistently faster, so I will stick to your recommendation and drop the other way (I wanted to show the user how to use pure DataFrames.jl solution, but you are right that it is better to show good solutions).

[bkamins]

Thank you for the patience and scrutiny as always :).

[bkamins]

@nalimilan Thank you.