Document new function translations in 7.0

[roji]

• Query: add translation for string.IndexOf(string, int) efcore#25396
• Cosmos: Translate regex matching efcore#28078
• Custom aggregate translations efcore#28110
• Translate spatial aggregates efcore#28115

[amunim]

May I ask, do we use string.Join normally or by some method defined here?

[roji]

@amunim for string.Join you can just use that function as you normally would, e.g. within a Select following a GroupBy.

[amunim]

Thank you