Update createColumns() doc

[lolcabanon]

Added warning to avoid formatting id so that svelte-keyed will not parse it wrongly.

I added it as tip but was wondering is a warning would be better since it fails to execute.

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It gave me an error while I used column_id[x] in a for loop to generate columns.

TypeError: Cannot set properties of undefined (setting '0')

Here's the full call stack :

TypeError: Cannot set properties of undefined (setting '0')
    at /home/gugul/DEV/CRCATNQ/sveltekit-demo/node_modules/.pnpm/svelte-keyed@2.0.0_svelte@4.2.11/node_modules/svelte-keyed/dist/index.js:40:59
    at Object.update (/home/gugul/DEV/CRCATNQ/sveltekit-demo/node_modules/.pnpm/svelte@4.2.11/node_modules/svelte/src/runtime/store/index.js:69:7)
    at Object.set (/home/gugul/DEV/CRCATNQ/sveltekit-demo/node_modules/.pnpm/svelte-keyed@2.0.0_svelte@4.2.11/node_modules/svelte-keyed/dist/index.js:35:16)
    at /home/gugul/DEV/CRCATNQ/sveltekit-demo/node_modules/.pnpm/svelte-headless-table@0.18.2_svelte@4.2.11/node_modules/svelte-headless-table/dist/plugins/addColumnFilters.js:67:33
...

[coveralls]

Pull Request Test Coverage Report for Build 7966009360

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 59.766%

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Totals
Change from base Build 7758063433:	0.0%
Covered Lines:	2616
Relevant Lines:	4570

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💛 - Coveralls

[lolcabanon]

After seeing the preview, I think I prefer the result like this. Tell me what you think of it!

[bryanmylee]

This is a great catch! I would've never thought to document this, thanks!