Document new OQL feature: INSERT ... VALUES

[passalaqua]

To be released with 11.13.

[dahfjkg]

Passed team review

[MarkvanMents]

Thanks for the PR @passalaqua
I've expanded the introduction to explain what each option does, rather than just leap into the syntax.
I've also tried to expand the syntax description to try to make it clear what you can use. I found the explanation of a "valid expression" was a bit unclear in the terminology so I've tried to clarify.
Hope I haven't made things worse!

[MarkvanMents]

I think we should add a bit more information here:

Suggested change

	Available from Mendix version 11.6.0 when sourcing data from an oql query.
	Available from Mendix version 11.13.0 when using `VALUES` to specify rows directly.
	{{% /alert %}}
	The syntax of `INSERT` statements is:
	`INSERT` statements can be written with values or queries.
	You can use the `INSERT` statement to insert new entity objects into your data. You can do this in two ways:
	* using an OQL query – extracting data and use it to insert one or more new objects
	* using values – specifying explicit values and use these to insert one or more new objects
	{{% alert color="info" %}}
	Available from Mendix version 11.6.0.
	You can use an OQL query from Mendix version 11.6.0.
	You can use values from Mendix version 11.13.0.
	{{% /alert %}}

[MarkvanMents]

Suggested change

	### `INSERT` with query
	### `INSERT` with OQL Query
	Insert with OQL query allows you to extract data using an OQL query and insert those values as one or more entity objects.

[MarkvanMents]

Suggested change

	### `INSERT` with `VALUES`
	### `INSERT` with Values
	Insert with values allows you to insert a list of literals or OQL parameters as one or more entity objects.

[MarkvanMents]

Suggested change

	* `expression n` is any valid OQL expression with literals or OQL parameters.
	Every row must contain the same number of values of compatible types.
	This query can *not* select data from any entities.
	* `expression x` is any valid expression consisting solely of literals or OQL expressions. Every row must contain the same number of values of compatible types as the list of attributes you are inserting for each entity object.
	{{% alert color="info" %}}This expression cannot use OQL clauses to select data from any entities.{{% /alert %}}

[MarkvanMents]

Suggested change

	* `attribute` is an attribute of the entity that will be inserted.
	* `attribute` is an attribute of the entity that will be inserted.
	{{% alert color="info" %}}You cannot insert associations when inserting with values.{{% /alert %}}