Add release note

documentation/new-notes/PR-801.md

@@ -0,0 +1,7 @@
+### errlogInit can be run more than once
+
+Previously, running `errlogInit` after initialisation would silently fail. It is
+now possible to call `errlogInit` or `errlogInit2` multiple times in order to
+increase the buffer size.
+
+Note that it is not possible to _shrink_ the buffer size.