feat: VS Code snippets (#757)

Closes #756

### Summary of Changes

Various snippets for program elements with lengthy syntax.

packages/safe-ds-vscode/package.json

@@ -86,7 +86,13 @@
                 "editor.wordSeparators": "`~!@#%^&*()-=+[]{}\\|;:'\",.<>/?»«",
                 "files.trimTrailingWhitespace": true
             }
-        }
+        },
+        "snippets": [
+            {
+                "language": "safe-ds",
+                "path": "./snippets/safe-ds.json"
+            }
+        ]
     },
     "type": "module",
     "main": "dist/extension/mainClient.cjs",

packages/safe-ds-vscode/snippets/safe-ds.json

@@ -0,0 +1,82 @@
+{
+    "Import": {
+        "prefix": ["from", "import"],
+        "body": ["from $1 import $0"],
+        "description": "Import of declarations from a package."
+    },
+    "Minimal Annotation": {
+        "prefix": ["minimal-annotation"],
+        "body": ["annotation ${0:MyAnnotation}"],
+        "description": "A minimal annotation."
+    },
+    "Annotation": {
+        "prefix": ["annotation"],
+        "body": ["annotation ${1:MyAnnotation}${2:($3)} ${4:where {$0\\}}"],
+        "description": "An annotation."
+    },
+    "Attribute": {
+        "prefix": ["attribute"],
+        "body": ["${1|static |}attr ${2:myAttribute}: $0"],
+        "description": "An attribute."
+    },
+    "Minimal Class": {
+        "prefix": ["minimal-class"],
+        "body": ["class ${0:MyClass}"],
+        "description": "A minimal class."
+    },
+    "Class": {
+        "prefix": ["class"],
+        "body": ["class ${1:MyClass}${2:<$3>}${4:($5)} ${6:sub $7} ${8:where {$9\\}} ${10:{$0\\}}"],
+        "description": "A class."
+    },
+    "Enum": {
+        "prefix": ["enumeration"],
+        "body": ["enum ${1:MyEnum} {", "    $0", "}"],
+        "description": "An enumeration."
+    },
+    "Minimal Function": {
+        "prefix": ["minimal-function"],
+        "body": ["fun ${1:myFunction}($0)"],
+        "description": "A minimal function."
+    },
+    "Function": {
+        "prefix": ["function", "method"],
+        "body": ["${1|static |}fun ${2:myFunction}${3:<$4>}($5) ${6:-> ($7)} ${8:where {$0\\}}"],
+        "description": "A function."
+    },
+    "Schema": {
+        "prefix": ["schema"],
+        "body": ["schema ${1:MySchema} {", "    $0", "}"],
+        "description": "A schema."
+    },
+    "Pipeline": {
+        "prefix": ["pipeline"],
+        "body": ["pipeline ${1:MyPipeline} {", "    $0", "}"],
+        "description": "A pipeline."
+    },
+    "Segment": {
+        "prefix": ["segment"],
+        "body": ["${1|internal ,private |}segment ${2:mySegment}($3) ${4:-> ($5)} {", "    $0", "}"],
+        "description": "A segment."
+    },
+    "Block Lambda": {
+        "prefix": ["block-lambda"],
+        "body": ["($1) -> {", "    $0", "}"],
+        "description": "A lambda that executes a list of statements."
+    },
+    "Expression Lambda": {
+        "prefix": ["expression-lambda"],
+        "body": ["($1) -> $0"],
+        "description": "A lambda that returns a single expression."
+    },
+    "Block Comment": {
+        "prefix": ["block-comment"],
+        "body": ["/*", " * $0", " */"],
+        "description": "A block comment."
+    },
+    "Documentation Comment": {
+        "prefix": ["documentation-comment"],
+        "body": ["/**", " * $0", " */"],
+        "description": "A documentation comment."
+    }
+}