Update scripting.asciidoc
Update scripting.asciidoc

Fix script syntax for script_score

Closes #15096
strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test