Example in docs is incorrect/incomplete

[ErikBuer]

I can't run the code in the example.

https://github.com/JuliaGNSS/Tracking.jl/blob/d34a870addf05d81246ce98e466d8d8527816309/docs/src/index.md?plain=1#L60C1-L71C4

Running the example in a reply yields the following error:

julia> state = TrackingState(GPSL1, carrier_doppler, code_phase)
ERROR: MethodError: no method matching TrackingState(::Type{GPSL1}, ::Unitful.Quantity{Int64, 𝐓⁻¹, Unitful.FreeUnits{(Hz,), 𝐓⁻¹, nothing}}, ::Int64)
The type `TrackingState` exists, but no method is defined for this combination of argument types when trying to construct it.

Closest candidates are:
  TrackingState(::S, ::Any, ::Any; code_doppler, carrier_phase, carrier_loop_filter, code_loop_filter, sc_bit_detector, num_ants, correlator, integrated_samples, prompt_accumulator, cn0_estimator) where S<:GNSSSignals.AbstractGNSS
   @ Tracking ~/.julia/packages/Tracking/lSwFl/src/tracking_state.jl:105
  TrackingState(::S, ::Unitful.Quantity{Float64, 𝐓⁻¹, Unitful.FreeUnits{(Hz,), 𝐓⁻¹, nothing}}, ::Unitful.Quantity{Float64, 𝐓⁻¹, Unitful.FreeUnits{(Hz,), 𝐓⁻¹, nothing}}, ::Unitful.Quantity{Float64, 𝐓⁻¹, Unitful.FreeUnits{(Hz,), 𝐓⁻¹, nothing}}, ::Unitful.Quantity{Float64, 𝐓⁻¹, Unitful.FreeUnits{(Hz,), 𝐓⁻¹, nothing}}, ::Float64, ::Float64, ::C, ::CALF, ::COLF, ::SecondaryCodeOrBitDetector, ::Int64, ::ComplexF64, ::CN, ::DS, ::CAR, ::COR) where {S<:GNSSSignals.AbstractGNSS, C<:Tracking.AbstractCorrelator, CALF<:TrackingLoopFilters.AbstractLoopFilter, COLF<:TrackingLoopFilters.AbstractLoopFilter, CN<:AbstractCN0Estimator, DS<:Tracking.DownconvertedSignalCPU, CAR<:Tracking.CarrierReplicaCPU, COR<:Vector{Int8}}
   @ Tracking ~/.julia/packages/Tracking/lSwFl/src/tracking_state.jl:70

Stacktrace:
 [1] top-level scope
   @ REPL[7]:1

Perhaps one should write the example as an @example to ensure its validity.

[ErikBuer]

It seems the problem is in passing the type GPSL1.

Should be:

state = TrackingState(GPSL1(), carrier_doppler, code_phase)