bug: regression after 0.23.0 to 0.24.0 update

[antongolub]

https://github.com/google/zx/actions/runs/3058307300/jobs/4934368868#step:5:9

Cannot read properties of undefined (reading 'flags')
Error: Process completed with exit code 1.

https://github.com/SamVerschueren/tsd/compare/v0.23.0...v0.24.0#diff-77e120f3feff540d10e6e6e104aa06b7a7d08cc27d1da30666fd899a080f4736R27

    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
    const maybeAlias = checker.getSymbolAtLocation(expression)!;
    const symbol = maybeAlias.flags & SymbolFlags.Alias ?
        checker.getAliasedSymbol(maybeAlias) :
        maybeAlias;

[sindresorhus]

// @tommy-mitchell