Fix microsoft/vscode#50807

Author: octref

src/services/scssCompletion.ts

@@ -145,7 +145,9 @@ export class SCSSCompletion extends CSSCompletion {
 		},
 		{
 			label: "@if",
-			documentation: localize("scss.builtin.@if", "Includes the body if the expression does not evaluate to `false` or `null`.")
+			documentation: localize("scss.builtin.@if", "Includes the body if the expression does not evaluate to `false` or `null`."),
+			insertText: "@if ${1:expr} {\n\t$0\n}",
+			insertTextFormat: InsertTextFormat.Snippet
 		},
 		{
 			label: "@for",

src/test/scss/scssCompletion.test.ts

@@ -95,7 +95,7 @@ suite('SCSS - Completions', () => {
 				{ label: '@debug' },
 				{ label: '@warn' },
 				{ label: '@error' },
-				{ label: '@if' },
+				{ label: '@if', insertTextFormat: InsertTextFormat.Snippet },
 				{ label: '@for', insertTextFormat: InsertTextFormat.Snippet },
 				{ label: '@each', insertTextFormat: InsertTextFormat.Snippet },
 				{ label: '@while', insertTextFormat: InsertTextFormat.Snippet },
@@ -166,8 +166,7 @@ suite('SCSS - Completions', () => {
 				{ label: '@while' },
 				{ label: '@mixin' },
 				{ label: '@include' }
-
 			]
-		})
+		});
 	});
 });