Fix string interpolation in error messages

asm.js

@@ -680,7 +680,8 @@ export class Assembler {
               ?? this.lookup_global(action.symbol)
               ?? this.lookup_def(action.symbol);
         if (value == null) {
-            console.error(`ERROR: Unable to resolve symbol {action.symbol}`);
+            console.error(
+                `ERROR: Unable to resolve symbol ${action.symbol}`);
             value = 0;
         }
         func.body.push(value);
@@ -710,7 +711,7 @@ export class Assembler {
     action_at(action) {
         const mem = Object.keys(this.mems).indexOf(action.at.mem);
         if (mem == -1) {
-            console.error(`ERROR: No memory named {action.at.mem}`);
+            console.error(`ERROR: No memory named ${action.at.mem}`);
             return;
         }
         this.pos.mem = mem;