Docs: Allow snippets to have line continuation (#32649)

Currently, snippets in lists cannot be rendered correctly as a console command because the console command requires a line continuation '+'. This allows snippets to have a line continuation between the snippet and the // CONSOLE.

buildSrc/src/main/groovy/org/elasticsearch/gradle/doc/SnippetsTask.groovy

@@ -284,6 +284,10 @@ public class SnippetsTask extends DefaultTask {
                     contents.append(line).append('\n')
                     return
                 }
+                // Allow line continuations for console snippets within lists
+                if (snippet != null && line.trim() == '+') {
+                    return
+                }
                 // Just finished
                 emit()
             }