[ES|QL] Removes highlighting from script as it is being provided by ES docs already (elastic#215631)

## Summary

This PR elastic/elasticsearch#125251 adds
highlighting for the code blocks so it is not needed to be added on the
kibana side. This PR removes it.

I didnt run the script because it will remove the highlighting. It will
run next Monday with @craigtaverner 's PR being merged

(cherry picked from commit 935fc0f)

Author: stratoula

src/platform/packages/private/kbn-language-documentation/scripts/generate_esql_docs.ts

@@ -104,10 +104,7 @@ function writeFunctionDocs(functionDocs: Map<string, DocsSectionContent>, pathTo
       doc.description,
       Array.from(functionDocs.keys())
     );
-    const defaultMessage = replaceCodeBlocksForESQLFormatting(docWithoutLinks).replaceAll(
-      '`',
-      '\\`'
-    );
+    const defaultMessage = docWithoutLinks.replaceAll('`', '\\`');
     return `
   const foo = 
   // Do not edit manually... automatically generated by scripts/generate_esql_docs.ts
@@ -178,10 +175,6 @@ function removeAsciiDocInternalCrossReferences(asciidocString: string, functionN
   });
 }
 
-function replaceCodeBlocksForESQLFormatting(text: string) {
-  return text.replace(/```(\n[\s\S]*?\n)```/g, '``` esql$1```');
-}
-
 /**
  * This function searches the AST for the functions list
  */