Fix fitted_mean docstring

[raphaelsaavedra]

Docstring had initial_params as a positional argument rather than kwarg.

[codecov]

Codecov Report

Merging #137 (5b2f7f3) into master (e779144) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #137      +/-   ##
==========================================
- Coverage   97.12%   97.12%   -0.01%     
==========================================
  Files          32       31       -1     
  Lines         940      938       -2     
==========================================
- Hits          913      911       -2     
  Misses         27       27              

Impacted Files	Coverage Δ
src/univariate_score_driven_recursion.jl	88.15% <ø> (ø)
src/prints.jl	100.00% <0.00%> (ø)
src/opt_methods/IPNewton.jl	100.00% <0.00%> (ø)
src/distributions/tdistlocationscale.jl	100.00% <0.00%> (ø)
src/ScoreDrivenModels.jl

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