Consolidate F# optional parameters documentation

Co-authored-by: gewarren <[email protected]>

Author: Copilot

docs/fsharp/language-reference/members/methods.md

@@ -95,16 +95,7 @@ Overloaded methods are methods that have identical names in a given type but tha
 
 ## Optional Arguments
 
-Starting with F# 4.1, you can also have optional arguments with a default parameter value in methods.  This is to help facilitate interoperation with C# code.  The following example demonstrates the syntax:
-
-```fsharp
-open System.Runtime.InteropServices
-// A class with a method M, which takes in an optional integer argument.
-type C() =
-    member _.M([<Optional; DefaultParameterValue(12)>] i) = i + 1
-```
-
-Note that the value passed in for `DefaultParameterValue` must match the input type.  In the above sample, it is an `int`.  Attempting to pass a non-integer value into `DefaultParameterValue` would result in a compile error.
+F# supports optional arguments for methods. For detailed information about the different forms of optional arguments available in F#, see [Optional Parameters](../parameters-and-arguments.md#optional-parameters).
 
 ## Example: Properties and Methods
 

docs/fsharp/language-reference/parameters-and-arguments.md

@@ -124,6 +124,10 @@ Note that those members could perform any arbitrary work, the syntax is effectiv
 
 ## Optional Parameters
 
+F# supports two distinct forms of optional parameters for methods, each serving different purposes:
+
+### Optional Arguments with Late Defaults (F# Native)
+
 You can specify an optional parameter for a method by using a question mark in front of the parameter name. From the callee's perspective, optional parameters are interpreted as the F# option type, so you can query them in the regular way that option types are queried, by using a `match` expression with `Some` and `None`. Optional parameters are permitted only on members, not on functions created by using `let` bindings.
 
 You can pass existing optional values to method by parameter name, such as `?arg=None` or `?arg=Some(3)` or `?arg=arg`. This can be useful when building a method that passes optional arguments to another method.
@@ -145,7 +149,9 @@ Baud Rate: 9600 Duplex: Full Parity: false
 Baud Rate: 4800 Duplex: Half Parity: false
 ```
 
-For the purposes of C# and Visual Basic interop you can use the attributes `[<Optional; DefaultParameterValue<(...)>]` in F#, so that callers will see an argument as optional. This is equivalent to defining the argument as optional in C# as in `MyMethod(int i = 3)`.
+### Optional Arguments with Early Defaults (C# Interop)
+
+For the purposes of C# and Visual Basic interop you can use the attributes `[<Optional; DefaultParameterValue<(...)>]` in F#, so that callers will see an argument as optional. This is equivalent to defining the argument as optional in C# as in `MyMethod(int i = 3)`. This form was introduced in F# 4.1 to help facilitate interoperation with C# code.
 
 ```fsharp
 open System