Minor ticks and grid lines docs

[LiamConnors]

Documentation PR

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• This change runs in the current version of Plotly on PyPI and targets the doc-prod branch OR it targets the master branch
• If this PR modifies the first example in a page or adds a new one, it is a px example if at all possible
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• Imports are plotly.graph_objects as go / plotly.express as px / plotly.io as pio
• Data frames are always called df
• fig = <something> call is high up in each new/modified example (either px.<something> or make_subplots or go.Figure)
• Liberal use is made of fig.add_* and fig.update_* rather than go.Figure(data=..., layout=...) in every new/modified example
• Specific adders and updaters like fig.add_shape and fig.update_xaxes are used instead of big fig.update_layout calls in every new/modified example
• fig.show() is at the end of each new/modified example
• plotly.plot() and plotly.iplot() are not used in any new/modified example
• Hex codes for colors are not used in any new/modified example in favour of these nice ones

Code PR

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• For a new feature or a change in behaviour, I have updated the relevant docstrings in the code to describe the feature or behaviour (please see the doc checklist as well).

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[nicolaskruchten]

Nice! Can you also add an example to the other axes pages like https://plotly.com/python/time-series/ and https://plotly.com/python/log-plot/ (if applicable) ?

[LiamConnors]

Nice! Can you also add an example to the other axes pages like https://plotly.com/python/time-series/ and https://plotly.com/python/log-plot/ (if applicable) ?

I added an example to time-series. It's not supported on log axes. I added a note to say where it isn't supported.

[archmoj]

By default ticks if being visible are located outside.
I suggest on the y-axis we demo how they could be placed inside.

[LiamConnors]

Good point. I've changed it to inside for the y-axis

[archmoj]

In addition to those predefined line types, one could use custom values for griddash e.g. "10px" | more info: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/stroke-dasharray

[LiamConnors]

@archmoj, should it work like this? That throws an error
fig.update_xaxes(showgrid=True, gridwidth=1, gridcolor='LightPink', griddash='10px')

[archmoj]

What is the error message?
Here is a codepen you could may adapt which also illustrate the case of "monthly period labels with weekly minor ticks".

[LiamConnors]

Created an issue for that #3710

[LiamConnors]

Thanks @archmoj I've added an example for "monthly period labels with weekly minor ticks".