Update prim-types.fsi (#12604)
Update prim-types.fsi (#12604)

fix typo in `lock` example (one char that makes me think the `lock` function does not work!)
dsyme/fsharp,dsyme/fsharp,dsyme/fsharp,dsyme/fsharp,dsyme/fsharp,dsyme/fsharp,dsyme/fsharp