Clarify type checking error message (#89525)
Previously:
```
pnpm next build
▲ Next.js 16.2.0-canary.28 (Turbopack)
Creating an optimized production build ...
✓ Compiled successfully in 5.7s
Running TypeScript ...
Failed to compile.
./app/page.tsx:3:5
Type error: Type 'string' is not assignable to type 'number'.
1 | import Nav from "../components/Nav";
2 |
> 3 | let x: number = 'abc'
| ^
4 |
5 |
6 | const IndexPage = () => (
Next.js build worker exited with code: 1 and signal: null
```
Now:
```
pnpm next build
▲ Next.js 16.2.0-canary.28 (Turbopack)
Creating an optimized production build ...
✓ Compiled successfully in 5.7s
Running TypeScript ...
Failed to type check.
./app/page.tsx:3:5
Type error: Type 'string' is not assignable to type 'number'.
1 | import Nav from "../components/Nav";
2 |
> 3 | let x: number = 'abc'
| ^
4 |
5 |
6 | const IndexPage = () => (
Next.js build worker exited with code: 1 and signal: null
```
