chore(toolkit-lib): fix typo in docs (#401)

---
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under the terms of the Apache-2.0 license

Author: mrgrain

.github/workflows/large-pr-checker.yml

@@ -402,7 +402,7 @@ declare const cx: ICloudAssemblySource;
 
 try {
   // Attempt a CDK Toolkit operation
-  const deployment = await cdk.deploy(cloudAssembly, {
+  const deployment = await cdk.deploy(cx, {
     stacks: ['MyStack']
   });
 

packages/@aws-cdk/toolkit-lib/README.md

@@ -61,6 +61,8 @@ export class LargePrChecker extends Component {
         | awk -F- '{print $NF}' \\
         | bc)
         
+        size=\${size:-0}
+        
         echo "Total lines changed: $size"
         echo "total_lines_changed=$size" >> $GITHUB_OUTPUT`,
         },