docs(readme): recipe to modify a style

[jdujava]

Description

Document the ability to modify the color palette of a style.

Related Issue(s)

See #595.

[github-actions[bot]]

This PR is stale because it has been open 30 days with no activity.

[jdujava]

I think this is still relevant :).

[MayRedwood]

This is not very clear - where, exactly, are we supposed to put that code?

[jdujava]

Neighboring examples also don't provide exact instructions on where to put the code. I personally put it in the config function in lazy spec for tokyonight like

config = function(_, opts)                                                       
    local styles = require('tokyonight.colors').styles                           

    -- change the colors for your new palette here                                          
    ---@type Palette                                                             
    local modified_colors = {                                                    
        bg_darker    = '#1a1a1a',                                                
        ...
    }                                                                            
    -- save as `custom` style (by extending the `storm` style)                                            
    styles.custom = vim.tbl_extend('force', styles.storm --[[@as Palette]], modified_colors)

    require('tokyonight').load(opts) -- load custom style (be sure to have opts.style = 'custom')

end,                                                                             

If it would be desirable, I have no problem including it in the recipe.

[github-actions[bot]]

This PR is stale because it has been open 30 days with no activity.

[jdujava]

Is there a reason for not merging this yet?