Add setting to enable/disable markdown drop into editor

For #142990

extensions/markdown-language-features/package.json

@@ -407,6 +407,12 @@
           "default": "off",
           "description": "%markdown.trace.desc%",
           "scope": "window"
+        },
+        "markdown.editor.drop.enabled": {
+          "type": "boolean",
+          "default": true,
+          "markdownDescription": "%configuration.markdown.editor.drop.enabled%",
+          "scope": "resource"
         }
       }
     },

extensions/markdown-language-features/package.nls.json

@@ -28,5 +28,6 @@
 	"configuration.markdown.links.openLocation.currentGroup": "Open links in the active editor group.",
 	"configuration.markdown.links.openLocation.beside": "Open links beside the active editor.",
 	"configuration.markdown.suggest.paths.enabled.description": "Enable/disable path suggestions for markdown links",
+	"configuration.markdown.editor.drop.enabled": "Enable/disable dropping into the markdown editor to insert shift. Requires enabling `#workbench.editor.dropIntoEditor.enabled#`.",
 	"workspaceTrust": "Required for loading styles configured in the workspace."
 }

extensions/markdown-language-features/src/languageFeatures/dropIntoEditor.ts

@@ -10,6 +10,11 @@ import * as URI from 'vscode-uri';
 export function registerDropIntoEditor(selector: vscode.DocumentSelector) {
 	return vscode.languages.registerDocumentOnDropProvider(selector, new class implements vscode.DocumentOnDropProvider {
 		async provideDocumentOnDropEdits(document: vscode.TextDocument, position: vscode.Position, dataTransfer: vscode.DataTransfer, _token: vscode.CancellationToken): Promise<vscode.SnippetTextEdit | undefined> {
+			const enabled = vscode.workspace.getConfiguration('markdown', document).get('editor.drop.enabled', true);
+			if (!enabled) {
+				return;
+			}
+
 			const urlList = await dataTransfer.get('text/uri-list')?.asString();
 			if (!urlList) {
 				return undefined;