Allow trimming of whitespace

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

tests/cases/3-instructions@trim_whitespace.snap

@@ -0,0 +1,39 @@
+---
+source: tests/file_tests.rs
+expression: emit
+input_file: tests/cases/trim_whitespace.nomo
+---
+[
+    LoadFromContextToSlot {
+        name: "test" (6..10),
+        slot: VariableSlot {
+            index: 0,
+        },
+    },
+    JumpIfNotTrue {
+        emit_slot: VariableSlot {
+            index: 0,
+        },
+        jump: 5,
+    },
+    AppendContent {
+        content: "Hello" (19..24),
+    },
+    AppendContent {
+        content: " " (24..25),
+    },
+    LoadFromContextToSlot {
+        name: "stuff" (29..34),
+        slot: VariableSlot {
+            index: 1,
+        },
+    },
+    EmitFromSlot {
+        slot: VariableSlot {
+            index: 1,
+        },
+    },
+    Jump {
+        jump: 0,
+    },
+]