Document new DateOnly.DayNumber translations (#5042)

See dotnet/efcore#36189

Author: roji

entity-framework/core/providers/sql-server/functions.md

@@ -127,6 +127,7 @@ dateOnly.Day                                                | DATEPART(day, @dat
 dateOnly.DayOfYear                                          | DATEPART(dayofyear, @dateOnly)                                                  | EF Core 8.0
 dateOnly.Month                                              | DATEPART(month, @dateOnly)                                                      | EF Core 8.0
 dateOnly.Year                                               | DATEPART(year, @dateOnly)                                                       | EF Core 8.0
+dateOnly.DayNumber                                          | DATEDIFF(day, '0001-01-01', @dateOnly)                                          | EF Core 10.0
 EF.Functions.AtTimeZone(dateTime, timeZone)                 | @dateTime AT TIME ZONE @timeZone                                                | EF Core 7.0
 EF.Functions.DateDiffDay(start, end)                        | DATEDIFF(day, @start, @end)
 EF.Functions.DateDiffHour(start, end)                       | DATEDIFF(hour, @start, @end)

entity-framework/core/providers/sqlite/functions.md

@@ -72,6 +72,7 @@ dateOnly.DayOfYear              | strftime('%j', @dateOnly)
 DateOnly.FromDateTime(dateTime) | date(@dateTime)                                                          | EF Core 8.0
 dateOnly.Month                  | strftime('%m', @dateOnly)
 dateOnly.Year                   | strftime('%Y', @dateOnly)
+dateOnly.DayNumber              | CAST(julianday(@dateOnly) - julianday('0001-01-01') AS INTEGER)          | EF Core 10.0
 DateTime.Now                    | datetime('now', 'localtime')
 DateTime.Today                  | datetime('now', 'localtime', 'start of day')
 DateTime.UtcNow                 | datetime('now')

entity-framework/core/what-is-new/ef-core-10.0/whatsnew.md

@@ -130,7 +130,8 @@ See [#12793](https://github.com/dotnet/efcore/issues/12793) and [#35367](https:/
 
 ### Other query improvements
 
-- Translate DateOnly.ToDateTime(timeOnly) ([#35194](https://github.com/dotnet/efcore/pull/35194), contributed by [@mseada94](https://github.com/mseada94)).
+- Translate [DateOnly.ToDateTime()](/dotnet/api/system.dateonly.todatetime) ([#35194](https://github.com/dotnet/efcore/pull/35194), contributed by [@mseada94](https://github.com/mseada94)).
+- Translate [DateOnly.DayNumber](/dotnet/api/system.dateonly.daynumber) and `DayNumber` subtraction for SQL Server and SQLite ([#36183](https://github.com/dotnet/efcore/issues/36183)).
 - Optimize multiple consecutive `LIMIT`s ([#35384](https://github.com/dotnet/efcore/pull/35384), contributed by [@ranma42](https://github.com/ranma42)).
 - Optimize use of `Count` operation on `ICollection<T>` ([#35381](https://github.com/dotnet/efcore/pull/35381), contributed by [@ChrisJollyAU](https://github.com/ChrisJollyAU)).
 - Optimize `MIN`/`MAX` over `DISTINCT` ([#34699](https://github.com/dotnet/efcore/pull/34699), contributed by [@ranma42](https://github.com/ranma42)).