.Net Removing special "input" argument

[RogerBarreto]

Motivation and Context

Resolves #3887

Before:

var result = await kernel.InvokeAsync(excuseFunction, new("I missed the F1 final race"));

After:

var result = await kernel.InvokeAsync(excuseFunction, new() { ["input"] = "I missed the F1 final race" });

[stephentoub]

The mentions of "input" should be removed from

semantic-kernel/dotnet/src/SemanticKernel.Abstractions/Functions/KernelFunctionAttribute.cs

Lines 33 to 43 in ae64b16

	/// The special "input" parameter may only be declared once, and in such cases, it must be declared first.
	/// All other parameters must be of a primitive .NET type or
	/// a type attributed with <see cref="TypeConverterAttribute"/>. Functions may return a <see cref="Task"/>,
	/// <see cref="ValueTask"/>, any primitive .NET type or a type attributed with <see cref="TypeConverterAttribute"/>,
	/// or a <see cref="Task{TResult}"/> or <see cref="ValueTask{TResult}"/> of such a type.
	/// </para>
	/// <para>
	/// Parameters are populated based on a arguments of the same name. If no argument of the given name is present, but
	/// a default value was specified via either a <see cref="DefaultValueAttribute"/> or an optional value in the signature,
	/// that default value is used instead. If no default value was specified and it's the first parameter, the "input"
	/// argument will be used. Otherwise, if no value is available, the invocation will fail.

[dmytrostruk]

We should probably update PR description to describe new syntax for better visibility.

Before:

var result = await kernel.InvokeAsync(excuseFunction, new("I missed the F1 final race"));

After:

var result = await kernel.InvokeAsync(excuseFunction, new() { ["input"] = "I missed the F1 final race" });