Fix order of sections in Validation chapter of reference manual

Closes gh-32408

framework-docs/modules/ROOT/nav.adoc

@@ -39,8 +39,8 @@
 ** xref:core/resources.adoc[]
 ** xref:core/validation.adoc[]
 *** xref:core/validation/validator.adoc[]
-*** xref:core/validation/conversion.adoc[]
 *** xref:core/validation/beans-beans.adoc[]
+*** xref:core/validation/conversion.adoc[]
 *** xref:core/validation/convert.adoc[]
 *** xref:core/validation/format.adoc[]
 *** xref:core/validation/format-configuring-formatting-globaldatetimeformat.adoc[]
@@ -431,4 +431,4 @@
 ** xref:languages/groovy.adoc[]
 ** xref:languages/dynamic.adoc[]
 * xref:appendix.adoc[]
-* https://github.com/spring-projects/spring-framework/wiki[Wiki]
+* https://github.com/spring-projects/spring-framework/wiki[Wiki]