register output file in output folder, we have to write it to both source and output folder though

Author: Mpdreamz

src/Elastic.Documentation.Configuration/Diagram/DiagramRegistry.cs

@@ -83,6 +83,7 @@ public async Task<int> CreateDiagramCachedFiles(Cancel ctx)
 				if (directory != null && !_writeFileSystem.Directory.Exists(directory))
 					_ = _writeFileSystem.Directory.CreateDirectory(directory);
 
+				_logger.LogWarning("Creating local diagram:  {LocalPath}", localPath);
 				// Download SVG content
 				var svgContent = await _httpClient.GetStringAsync(diagramInfo.EncodedUrl, ct);
 

src/Elastic.Markdown/Myst/Directives/Diagram/DiagramBlock.cs

@@ -72,8 +72,11 @@ public override void FinalizeAndValidate(ParserContext context)
 		// only register SVG if we can look up the Markdown
 		if (context.DocumentationFileLookup(context.MarkdownSourcePath) is MarkdownFile currentMarkdown)
 		{
-			var path = context.Build.ReadFileSystem.FileInfo.New(Path.Combine(currentMarkdown.ScopeDirectory.FullName, localPath));
-			context.DiagramRegistry.RegisterDiagramForCaching(path, EncodedUrl);
+			var fs = context.Build.ReadFileSystem;
+			var scopePath = fs.FileInfo.New(Path.Combine(currentMarkdown.ScopeDirectory.FullName, localPath));
+			var relativeScopePath = fs.Path.GetRelativePath(context.Build.DocumentationSourceDirectory.FullName, scopePath.FullName);
+			var outputPath = fs.FileInfo.New(Path.Combine(context.Build.DocumentationOutputDirectory.FullName, relativeScopePath));
+			context.DiagramRegistry.RegisterDiagramForCaching(outputPath, EncodedUrl);
 		}
 		else
 			this.EmitError($"Can not locate markdown source for {context.MarkdownSourcePath} to register diagram for caching.");