CheckForOverflowUnderflow property does not enable overflow checking, as the documentation implies

**Repro steps**

Create and run a simple project like this:

```

Exe
net5.0
true

```

Program.fs

```
[]
let main argv =
printfn "%d" (System.Int32.MaxValue + 1)
0
```

**Expected behavior**

OverflowException is thrown, because overflow checking was enabled by CheckForOverflowUnderflow=true. The [compiler options documentation](https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/compiler-options) says

> --checked[+\|-] | Enables or disables the generation of overflow checks. This compiler option is equivalent to the C# compiler option of the same name. For more information, see [/checked (C# Compiler Options)](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-options/language#checkforoverflowunderflow).

and the linked C# compiler options page says

> The CheckForOverflowUnderflow option specifies whether an integer arithmetic statement that results in a value that is outside the range of the data type causes a run-time exception.
> `true`

This led me to believe that `true` would also work for F#.

**Actual behavior**

-2147483648 is printed, because overflow checking is actually not enabled.

**Known workarounds**

Add this to the project instead:

`--checked+`

**Related information**

At minimum the documentation should be clarified, but it would be much better to make the CheckForOverflowUnderflow property work, of course.

F# Compiler version 11.0.0.0 for F# 5.0

* Operating system: Windows 7 x64
* .NET Runtime kind: .NET 5.0.4
* Editing Tools: VS 2019, Rider