Rewrite Kibana docs asciidoc links to be MD links (elastic#125155)

Did a few things:
* Rewrite Kibana docs asciidoc links to be MD links
* Make kibana docs links absolute to planned publication path
* Clarify which operators are generated and which are static
* Removed the trailing .md from kibana docs links

Author: craigtaverner

docs/reference/query-languages/esql/_snippets/operators/examples/cast.md

@@ -1,5 +1,3 @@
-% This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
-
 **Example**
 
 ```esql

docs/reference/query-languages/esql/_snippets/operators/examples/predicates.md

@@ -1,5 +1,3 @@
-% This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
-
 **Examples**
 
 ```esql

x-pack/plugin/esql/build.gradle

@@ -167,6 +167,13 @@ tasks.named("test").configure {
 
       List kibana = kibanaTree.files.collect { it.name }
       int countKibana = kibana.size()
+      Closure replaceLinks = line -> {
+        // The kibana docs are not deployed to the normal docs location, so need absolute paths for internal references
+        line.replaceAll(
+          /\]\(\/reference\/([^)\s]+)\.md(#\S+)?\)/,
+          '](https://www.elastic.co/docs/reference/elasticsearch/$1$2)'
+        )
+      }
       if (countKibana == 0) {
         logger.quiet("ESQL Docs: No function/operator kibana docs created. Skipping sync.")
       } else {
@@ -181,6 +188,7 @@ tasks.named("test").configure {
               include '**/*.md', '**/*.json'
             }
           }
+          filter replaceLinks
         }
       }
     }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/DocsV3Support.java

@@ -142,7 +142,8 @@ public static void renderNegatedOperator(
             entry("esql-time-spans", "esql/esql-time-spans.md"),
             entry("esql-limitations", "esql/limitations.md"),
             entry("esql-function-named-params", "esql/esql-syntax.md"),
-            entry("query-dsl-query-string-query", "query-dsl/query-dsl-query-string-query.md")
+            entry("query-dsl-query-string-query", "query-dsl/query-dsl-query-string-query.md"),
+            entry("regexp-syntax", "query-dsl/regexp-syntax.md")
         );
         // Static links to the commands file
         knownCommands = Map.ofEntries(entry("where", "where"), entry("stats-by", "stats"));
@@ -626,7 +627,7 @@ void renderDetailedDescription(String detailedDescription, String note) throws I
             StringBuilder rendered = new StringBuilder();
             if (Strings.isNullOrEmpty(detailedDescription) == false) {
                 detailedDescription = replaceLinks(detailedDescription.trim());
-                rendered.append("\n").append(detailedDescription).append("\n");
+                rendered.append(DOCS_WARNING).append(detailedDescription).append("\n");
             }
 
             if (Strings.isNullOrEmpty(note) == false) {
@@ -770,7 +771,7 @@ void renderKibanaInlineDocs(String name, FunctionInfo info) throws IOException {
 
             """);
         builder.append("### ").append(name.toUpperCase(Locale.ROOT)).append("\n");
-        builder.append(removeAsciidocLinks(info.description())).append("\n\n");
+        builder.append(replaceLinks(info.description())).append("\n\n");
 
         if (info.examples().length > 0) {
             Example example = info.examples()[0];
@@ -779,7 +780,7 @@ void renderKibanaInlineDocs(String name, FunctionInfo info) throws IOException {
             builder.append("\n```\n");
         }
         if (Strings.isNullOrEmpty(info.note()) == false) {
-            builder.append("Note: ").append(removeAsciidocLinks(info.note())).append("\n");
+            builder.append("Note: ").append(replaceLinks(info.note())).append("\n");
         }
         String rendered = builder.toString();
         logger.info("Writing kibana inline docs for [{}]:\n{}", name, rendered);