Add for loop

Signed-off-by: Marcel Müller <neikos@neikos.email>

tests/cases/2-ast@simple_for.snap

@@ -0,0 +1,44 @@
+---
+source: tests/file_tests.rs
+expression: ast
+info:
+  context:
+    values:
+      - one
+      - two
+input_file: tests/cases/simple_for.nomo
+---
+TemplateAst {
+    root: [
+        ForChain {
+            for_block: Block {
+                prev_whitespace_content: None,
+                expression: For {
+                    value_ident: [Ident]"value" (7..12),
+                    value_expression: VariableAccess(
+                        [Ident]"values" (16..22),
+                    ),
+                },
+                post_whitespace_content: None,
+            },
+            content: [
+                Interpolation {
+                    prev_whitespace_content: None,
+                    expression: VariableAccess(
+                        [Ident]"value" (36..41),
+                    ),
+                    post_whitespace_content: Some(
+                        [Whitespace]"\n" (44..45),
+                    ),
+                },
+            ],
+            else_block: None,
+            else_content: None,
+            end_block: Block {
+                prev_whitespace_content: None,
+                expression: EndBlock,
+                post_whitespace_content: None,
+            },
+        },
+    ],
+}