tutorials: fix incipit tutorial

[musicEnfanthen]

This PR adds some improvements for the incipit tutorial, including those proposed in #263 by @mfeustle .

This includes :

• simplifying the note example in step 4;
• simplifying and improving readability of the xml:ids used in the final step;
• improving the explanation of the attributes used in the final step;
• improving the explanation of the referencing mechanism with xml:ids in the final step;
• fixing a typo in the title of the incipit tutorial in the Spanish translation.

Fixes #263

[musicEnfanthen]

@martha-thomae May I ask you to have a look at the updated Spanish translations?

[rettinghaus]

@martha-thomae Could you have a look please?

[bwbohl]

pinging reviewers

[martha-thomae]

Thanks, Benni, Klaus, and Stefan, I will look at this during this week to get it done :)

[martha-thomae]

A few minor corrections for the writing in Spanish. And one extra paragraph that was missing in the Spanish translation of the English version. Thanks for all your work, @musicEnfanthen!

One small question (@musicEnfanthen, @rettinghaus, @bwbohl), do you remember how could I check from my own fork a branch of another person? Like this branch from Stefan, how can I see it on my fork to be able to run the website and see the changes locally? and also be able to actually make commits here? Thank you!

[bwbohl]

A few minor corrections for the writing in Spanish. And one extra paragraph that was missing in the Spanish translation of the English version. Thanks for all your work, @musicEnfanthen!

One small question (@musicEnfanthen, @rettinghaus, @bwbohl), do you remember how could I check from my own fork a branch of another person? Like this branch from Stefan, how can I see it on my fork to be able to run the website and see the changes locally? and also be able to actually make commits here? Thank you!

@martha-thomae In your above comments you can click the document with-+and- to add a suggestion for the marked lines and add your changes there. Theses then can be committed directly.

I’ll make one example for the deletion of 'del ligado' above (#645 (comment))

[musicEnfanthen]

@martha-thomae Thanks for your review.

You can checkout any branch very easily by using gh cli tools: https://cli.github.com/ . You can then build the branch locally (see CONTRIBUTING.md for manual how to do that).

To propose changes to this PR, as @bwbohl explained, you can click on the "Files changed" tab at the top of this PR and then click on the +/- signs at the beginning of a changed line.

[martha-thomae]

Thanks @bwbohl and @musicEnfanthen for the help! I added now the actual changes :) thank you!

[martha-thomae]

I think this can be merged now :)