Docs: Move graal/mandrel version-for-documentation properties to docs…

… pom

The properties defining the GraalVM version are already located in
different files. Moving these properties to docs/pom.xml avoids running
all the CI jobs when altering them (which is the right thing to do as
they only affect the documentation).

build-parent/pom.xml

@@ -38,11 +38,6 @@
         <jandex-gradle-plugin.version>1.0.0</jandex-gradle-plugin.version>
 
         <!-- These properties are needed in order for them to be resolvable by the documentation -->
-        <!-- The Graal version we suggest using in documentation - as that's
-           what we work with by self downloading it: -->
-        <graal-sdk.version-for-documentation>22.2</graal-sdk.version-for-documentation>
-        <mandrel.version-for-documentation>22.2</mandrel.version-for-documentation>
-
         <asciidoctorj.version>2.5.7</asciidoctorj.version>
         <htmlunit.version>2.40.0</htmlunit.version>
         <javaparser-core.version>3.24.2</javaparser-core.version>

docs/pom.xml

@@ -15,6 +15,11 @@
 
     <packaging>jar</packaging>
     <properties>
+        <!-- The Graal version we suggest using in documentation - as that's
+           what we work with by self downloading it: -->
+        <graal-sdk.version-for-documentation>22.2</graal-sdk.version-for-documentation>
+        <mandrel.version-for-documentation>22.2</mandrel.version-for-documentation>
+
         <asciidoctor-maven-plugin.version>2.0.0</asciidoctor-maven-plugin.version>
         <asciidoctorj-pdf.version>1.5.0-beta.8</asciidoctorj-pdf.version>
         <roaster-jdt.version>2.26.0.Final</roaster-jdt.version>