Apply SEO fix as per https://github.com/jakartaee/platform/issues/1108

spec/pom.xml

diff --git a/spec/pom.xml b/spec/pom.xml
index f99a201..288547e 100644
--- a/spec/pom.xml
+++ b/spec/pom.xml
@@ -175,6 +175,7 @@
                                 <source-highlighter>coderay</source-highlighter>
                                 <imagesdir>images</imagesdir>
                                 <doctype>book</doctype>
+                                <docinfo>private-head</docinfo>
                                 <status>${status}</status>
                                 <data-uri />
                                 <icons>font</icons>

spec/src/main/asciidoc/expression-language-spec-docinfo.html

diff --git a/spec/src/main/asciidoc/expression-language-spec-docinfo.html b/spec/src/main/asciidoc/expression-language-spec-docinfo.html
new file mode 100644
index 0000000..fb9d72d
--- /dev/null
+++ b/spec/src/main/asciidoc/expression-language-spec-docinfo.html
@@ -0,0 +1 @@
+<link rel="canonical" href="https://jakarta.ee/specifications/expression-language/6.1/jakarta-expression-language-spec-6.1">
\ No newline at end of file