[5.0.x] Added release date for 5.0.12 and 4.2.19.

Backport of 294cc965efe0dfc8457aa5a8e78cb6d53abfcf92 from main.

docs/releases/4.2.19.txt

@@ -2,7 +2,7 @@
 Django 4.2.19 release notes
 ===========================
 
-*Expected February 5, 2025*
+*February 5, 2025*
 
 Django 4.2.19 fixes a regression in 4.2.18.
 

docs/releases/5.0.12.txt

@@ -2,7 +2,7 @@
 Django 5.0.12 release notes
 ===========================
 
-*Expected February 5, 2025*
+*February 5, 2025*
 
 Django 5.0.12 fixes a regression in 5.0.11.