update JDK compat page for 2.12.18 release

Author: SethTisue

_overviews/jdk-compatibility/overview.md

@@ -12,8 +12,8 @@ Sometimes new JVM and JDK (Java Development Kit) versions require us to update S
 
 | JDK version | Minimum Scala versions                                       |
 |:-----------:|:-------------------------------------------------------------|
-| 21 (ea)     | 3.3.1 (soon), 2.13.11 (soon), 2.12.18 (soon)                 |
-| 20          | 3.3.0, 2.13.11 (soon), 2.12.18 (soon)                        |
+| 21 (ea)     | 3.3.1 (soon), 2.13.11 (soon), 2.12.18                        |
+| 20          | 3.3.0, 2.13.11 (soon), 2.12.18                               |
 | 19          | 3.2.0, 2.13.9, 2.12.16                                       |
 | 18          | 3.1.3, 2.13.7, 2.12.15                                       |
 | 17 (LTS)    | 3.0.0, 2.13.6, 2.12.15                                       |
@@ -97,25 +97,25 @@ Support for JDK 19 was included in Scala 2.13.9 and 2.12.16.
 
 JDK 20, a non-LTS release, came out in March 2023.
 
-Support for JDK 20 is included in Scala 3.3.0.
+Support for JDK 20 was included in Scala 3.3.0 and 2.12.18.
 
 Support for JDK 20 has already been merged and is available in
 [nightly builds](https://stackoverflow.com/questions/40622878/how-do-i-tell-sbt-or-scala-cli-to-use-a-nightly-build-of-scala-2-12-or-2-13)
-of Scala 2.12 and 2.13.
+of 2.13.
 
-The support will be included in forthcoming Scala releases 2.12.18
-and 2.13.11.  We expect to release these in June 2023.
+The support will be included in the forthcoming Scala release
+2.13.11.  We expect to release it in June 2023.
 
 ## JDK 21 compatibility notes
 
 Early access builds of JDK 21 are already available. JDK 21 will
 be an LTS release.
 
 Initial support for JDK 21 has been merged and is already available in
-nightly builds of Scala 2.12, 2.13, and 3.
+Scala 2.12.18 and in nightly builds of Scala 2.13 and Scala 3.
 
-The support will be included in forthcoming Scala releases: 2.12.18,
-2.13.11, and 3.3.1.
+The support will be included in the forthcoming Scala releases
+2.13.11 and 3.3.1.
 
 ## GraalVM Native Image compatibility notes