Add info about 3.3 to source compat doc

Author: Kordyjan

docs/_docs/reference/language-versions/source-compatibility.md

@@ -23,6 +23,9 @@ The default Scala language syntax version currently supported by the Dotty compi
 - [`3.2-migration`](https://scala-lang.org/api/3.x/scala/runtime/stdLibPatches/language$$3/2-migration$.html): the same as `3.2`, but in conjunction with `-rewrite`, offer code rewrites from Scala `3.0/3.1` to `3.2`.
 - [`future`](https://scala-lang.org/api/3.x/scala/runtime/stdLibPatches/language$$future$.html): A preview of changes that will be introduced in `3.x` versions after `3.2`.
 Some Scala 2 specific idioms are dropped in this version. The feature set supported by this version may grow over time as features become stabilised for preview.
+- [`3.3`](https://scala-lang.org/api/3.x/scala/runtime/stdLibPatches/language$$3/3$.html): the same as `3.2`, but in addition:
+  -[Fewer braces syntax](https://docs.scala-lang.org/scala3/reference/other-new-features/indentation.html#optional-braces-for-method-arguments-1) is enabled by default.
+- [`3.3-migration`](https://scala-lang.org/api/3.x/scala/runtime/stdLibPatches/language$$3/3-migration$.html): the same as `3.3`
 
 - [`future-migration`](https://scala-lang.org/api/3.x/scala/runtime/stdLibPatches/language$$future-migration$.html): Same as `future` but with additional helpers to migrate from `3.2`. Similarly to the helpers available under `3.0-migration`, these include migration warnings and optional rewrites.