Bug 1861841 - Adjust relnoteversion for 2.53.18b1. r=frg

src/releases/2.53.18b1.en.html

@@ -1,7 +1,7 @@
 [%- PROCESS release.tmpl -%]
 [%- smversion = '2.53.18b1' -%]
 [%- prettyversion = '2.53.18 Beta 1' -%]
-[%- relnoteversion = '2.53.18b1' -%]
+[%- relnoteversion = '2.53.18' -%]
 [%- mirrorred = false -%]
 [%- uselongversion = false -%]
 [%- usefulldetails = true -%]