chore(tazjin/rlox): Wire scanner to interpreter to reduce warnings

... they're just noisy at the moment. This isn't complete because it
doesn't thread through scanner errors.

Change-Id: I0f75d2b20fa3f57be1af5d1d8aa8059856855825
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2162
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

users/tazjin/rlox/src/scanner.rs

@@ -133,3 +133,16 @@ impl<'a> Scanner<'a> {
         return self.tokens;
     }
 }
+
+pub fn scan<'a>(input: &'a [char]) -> Vec<Token<'a>> {
+    let scanner = Scanner {
+        source: &input,
+        tokens: vec![],
+        errors: vec![],
+        start: 0,
+        current: 0,
+        line: 0,
+    };
+
+    return scanner.scan_tokens();
+}