Format UnfoldSim docstrings according to template

[jschepers]

As pointed out by @cbrnr (#106), some of the docstrings are still incomplete and do not follow a common docstring convention. @cbrnr thanks a lot for pointing this out and for your suggestions on how to make the docstrings more consistent.

The goal is to transform the docstrings such that they match the docstring template, that I came up with based on the Julia manual, the Blue style guide and by checking the docstrings of other Julia packages.

I will post the current templates for Functions and Types below. However, please note that they are still subject to change when we find something that does not match the template.

@maanikmarathe, here is a list of all UnfoldSim.jl src files with docstrings. Once we are done with them, we can check the boxes. Also, feel free to post about docstrings for which you are unsure how to format them or where information is missing, either in this issue (#108) or by writing to me on Zulip. As discussed, I started from the top of the list and would like you to start from the bottom.

• bases.jl (@jschepers)
• component.jl (@jschepers)
• design.jl
• headmodel.jl
• helper.jl
• noise.jl
• onset.jl
• predefinedSimulations.jl
• simulation.jl
• types.jl

[jschepers]

Current templates:

Function docstring template

"""
    my_function(argument1:Type1; keyword_argument3::Type3 = value3)
    my_function(argument1::Type1, optional_argument2::Type2; keyword_argument3::Type3 = value3)

One-line description using the imperative form ("Do this") instead of the third person and ending with a period.

If the one-line description is not sufficient, one can also write a short paragraph with additional information.

# Arguments (if needed)
- `argument1::Type1`: Description of argument1.
- `optional_argument2::Type2` (optional): Description of optional_argument2.

# Keyword arguments (if needed)
- `keyword_argument3::Type3 = value3`: Description of keyword_argument3.

# Returns
- `result::Type4` : Description of result.

# Examples
```julia-repl
julia> my_function(value1, value2)
result1

julia> my_function(value1; keyword_argument3 = value4)
result2
```

See also [`my_function2`](@ref), [`my_function3`](@ref).
"""

Type docstring template

"""
    MyType <: MyAbstractType

One-line desciption of my type which ends with a period.

If the one-line description is not sufficient, one can also write a short paragraph with additional information.

# Fields
- `field1::Type1`: Description of field1.
- `optional_field2::Type2` (optional): Description of field2. If not provided, defaults to `value2`.

# Examples
```julia-repl
julia> MyType(field1, field2)
result1
```

See also [`MyType2`](@ref), [`my_function2`](@ref).
"""