Function isNotSymbol

isNotSymbol<T>(u: T): u is RelaxedExclude<T, symbol>
Type guard that checks if a value is not a symbol.

Type Narrowing Behavior:
- Excludes symbol from the input type when true
- Preserves all other types in the union
Type Parameters
- T
  The type of the input value
Parameters
- u: T
  The value to check
Returns u is RelaxedExclude<T, symbol>
true if u is not a symbol, false otherwise. When true, TypeScript excludes symbol from the type.
Example
```
const id = Symbol('id');
const tokens: unknown[] = [id, 'shared'];

const nonSymbols = tokens.filter(isNotSymbol);

assert.deepStrictEqual(nonSymbols, ['shared']);
```
- Defined in src/guard/is-type.mts:304