Two symbols are reported for override property

Hi there,

I'm not 100% sure this isn't by design and thus *think* it is a bug.

**Repro steps**

Add a test in `tests/service/Symbols.fs`

```fsharp
[]
let ``Override auto property`` () =
let source = """
module T

[]
type NodeBase() =
abstract member Children: int array

type StringNode() =
inherit NodeBase()
override val Children = Array.empty
"""
let _, checkResults = getParseAndCheckResults source
let symbols = checkResults.GetSymbolUsesAtLocation(10, 25, " override val Children = Array.empty", [ "Children" ])
let valSignatureTexts =
symbols
|> List.choose (fun su ->
match su.Symbol with
| :? FSharpMemberOrFunctionOrValue as mfv ->
mfv.GetValSignatureText(su.DisplayContext, su.Range)
| _ -> None
)

ignore valSignatureTexts
```

Provide the steps required to reproduce the problem:

- `checkResults.GetSymbolUsesAtLocation` will return two symbols. Both contain the correct range of the `override` in `StringNode`.

- However, the inner `ValRef` differs for both symbols.



**Expected behaviour**

I only get one symbol in this case. Maybe from the `override` Symbol I can go to the `abstract member Children` one.

**Actual behaviour**

Two symbols are found, leading to


**Known workarounds**

I can filter out the symbol I want by `DisplayName`.

**Related information**

Provide any related information (optional):

main branch at 0dfd880da573fbed6ab1008c9b53cc9aacf39f67