Fix Wikipedia link by escaping brackets

[denvitko]

Describe the problem

See the page about density matrix, part Trace and Positivity Conditions

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Its trace must be equal to one:

Remembering that the trace of a matrix (denoted as Tr) is the sum of its diagonal terms, we have:

Describe the expected solution

Try to escape the brackets with \, or see other options here.

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I'd do it, but wasn't sure how to make a push request. :/

[divshacker]

Hey @DenVitko Thanks for reporting this. Making a pull request is really easy. When you open Github repo of qiskit textbook You will see a option of forking it. Just fork the repo. Make a new branch, then change the files to fix this issue and then commit changes then open a pull request. It's very easy. This might help you.

[Anantha-Rao12]

Hi @divshacker @DenVitko I am unsure if the issue is with the text on the corresponding jupyter notebook. When I load the notebook locally, the extra bracket is absent. Not sure what is causing the issue on the textbook online.

[divshacker]

Yeah I have also tried to fix this issue but faced same issue which @Anantha-Rao12 is facing right now. Running the notebook locally don't give this error and all links are working. I think there must be some internal rendering problem. @frankharkins any suggestions?

[denvitko]

@divshacker @Anantha-Rao12 Have you tried any of those suggestions on stackoverflow ... the problem is with the brackets in the wiki link. It's interesting that locally it is rendered just right.

[frankharkins]

I think here you'll need to use an HTML link, i.e.:

<a href="https://en.wikipedia.org/wiki/Trace_(linear_algebra)">trace of a matrix</a>

which should work on both the notebook and the website.