Update docs for makeqr macro in qrcode plugin

[mateuszwilczek]

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name: Update docs for makeqr macro in qrcode plugin
about: Make the docs of the makeqr macro more practical by directly providing relevant context and usage examples

Is your PR related to a problem? Please describe.
The current docs for makeqr macro do not explain how to display a QR code, only how to generate data URI of an image.
The possible error correction levels are mentioned in a quote from external resource, without comprehensive explanation of what they do.

Describe the solution you are proposing
Add two examples of how to display an image with the QR code, instead of just generating a data URI.
Remove two old examples that wouldn't bring much now.
Add a table describing the error correction levels.
Remove the quote from external documentation site (but leave a link to it).

Describe alternatives you've considered
Other examples or a more elegant way of displaying a QR with dynamic content are always a possibility, I haven't come up with anything better.

Additional context
Screenshot of docs before changes:

Screenshot of docs after changes:

Handling of the base64 data URI might not be obvious to users less familiar with html.
I think it's practical to have a description of the correction levels directly in the plugin docs.
The macro/text substitution method of displaying a QR code with transcluded content is taken from $:/plugins/tiddlywiki/qrcode/make/MakeGenericQR.

Checklist before requesting a review

• Illustrate any visual changes (however minor) with before/after screenshots
• Self-review of code
• Documentation updates (for user-visible changes)
• Tests (for core code changes)
• Complies with coding style guidelines (for JavaScript code) -- N/A, no JS changes

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[github-actions]

Confirmed: mateuszwilczek has already signed the Contributor License Agreement (see contributing.md)

[Jermolene]

Thank you @mateuszwilczek looks good

[mateuszwilczek]

I don't have any ideas how to make the documentation any better, I'm marking this as ready for review and merging @Jermolene

[Jermolene]

Thank you @mateuszwilczek