Update use cases for the mode parameter in PDOStatement::fetchAll()

[colshrapnel]

Currently, case 3 makes no sense (PDO::FETCH_COLUMN|PDO::FETCH_UNIQUE would result in error) and case 4 is misleading (describing rather vanilla PDO::FETCH_GROUP's behavior). I added vanilla PDO::FETCH_UNIQUE and PDO::FETCH_GROUP cases and fixed PDO::FETCH_GROUP|PDO::FETCH_COLUMN.

Also, how does one remove a comment?

• 88699 is bogus, they need PDO::FETCH_UNIQUE but using PDO::FETCH_GROUP
• 122299 same as above
• 115175 is bogus, PDO::FETCH_UNIQUE|PDO::FETCH_GROUP makes no sense and effectively just PDO::FETCH_UNIQUE

[Girgias]

I deleted the notes, and suggested some phrasing improvements. Please let me know if they are correct or not.

[Girgias]

I think this reads better?

Suggested change

	To index the resulting array by certain column's value (instead of
	consecutive numbers), put this column's name first in the column
	list in SQL, and use <constant>PDO::FETCH_UNIQUE</constant>.
	This column must contain only unique values or some data will be lost.
	To index the resulting array by a certain column's value (instead of
	consecutive numbers), put this column's name first in the column
	list in SQL, and use <constant>PDO::FETCH_UNIQUE</constant>.
	This column must contain only unique values or some data will be lost.

[Girgias]

Suggested change

	To group results in the form of 3-dimensional array indexed by values
	of a specified column, put this column's name first in
	the column list in SQL and use <constant>PDO::FETCH_GROUP</constant>.
	To group results in the form of a 3-dimensional array indexed by values
	of a specified column, put this column's name first in
	the column list in SQL and use <constant>PDO::FETCH_GROUP</constant>.

[Girgias]

Suggested change

	To group results in the form of 2-dimensional array (which indices will
	be values of one column and values will be list arrays of values
	from another column, list only these 2 columns in the column list in SQL
	and use bitwise-OR <constant>PDO::FETCH_GROUP</constant> with
	<constant>PDO::FETCH_COLUMN</constant>.
	To group results in the form of a 2-dimensional array, whose indices will
	be the values of a column, and the associates values will be an array of values
	from a second column.
	Those 2 columns should be the only ones in the column list of the SQL,
	and <parameter>mode</parameter> must be a bitwise-OR of
	<constant>PDO::FETCH_GROUP</constant> with
	<constant>PDO::FETCH_COLUMN</constant>.