Improve error for a function declared inside another function

[Atomk]

Zig Version

0.11.0

Steps to Reproduce and Observed Output

Build a file containing the following code:

pub fn main() void {
    fn foo() void { }
}

The error:

test.zig:2:22: error: expected ';' after statement
    fn foo() void { }
                     ^

After adding the semicolon as suggested:

test.zig:2:8: error: function type cannot have a name
    fn foo() void { };
       ^~~

After removing the name as suggested:

test.zig:2:16: error: type 'fn() void' does not support array initialization syntax
    fn () void { };
    ~~~~~~~~~~~^~~
referenced by:
    callMain: zig-windows-x86_64-0.11.0\lib\std\start.zig:564:17
    initEventLoopAndCallMain: zig-windows-x86_64-0.11.0\lib\std\start.zig:508:34
    remaining reference traces hidden; use '-freference-trace' to see all reference traces

Expected Output

Something similar to:

test.zig:2:5: error: cannot create a function inside a function
    fn foo() void { };
    ^~~~~~~