Desktop: Resolves #15763: Reveal markup on mouseup instead of mousedown

[Rygaa]

Resolves #15763

I changed inline markup show from mousedown to mouseup. The cursor issue was not caused by mousedown.

Another issue: hidden link text was selected by accident. For [Joplin website](https://joplinapp.org), user sees only Joplin website, but CodeMirror sees full Markdown. Small mouse move could select hidden end part, like [Joplin website|](https://joplinapp.org)|. After Markdown was shown, hidden selection became highlighted text. Fix: on mouseup, if selected text is only hidden text, change it back to one cursor before showing Markdown.

Another issue: cursor did not go to the link end. After the hidden-selection fix, clicking at the end of shown Joplin website could still leave cursor before hidden link end: [Joplin website|](https://joplinapp.org). Fix: only for that end-click case, move cursor to full link end: [Joplin website](https://joplinapp.org)|. Middle click still stays inside link text.

Another issue: I also fixed links with space after (, like [label]( url). That space stayed visible while URL was hidden, so end click could put cursor near ( or URL. Fix: hide that space with URL.

Screen.Recording.2026-06-26.at.11.38.48.PM.mov

[coderabbitai]

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[bwat47]

I noticed one minor issue with selections, where when the markup reveals on mouseup, the selection is sometimes missing the markdown formatting characters (even though the selection covered the entire word):

Screencast.From.2026-06-27.08-03-19.mp4

edit: there can also be flickering during click and drag when the selection starts with hidden markdown formatting:

Screencast.From.2026-06-27.10-13-26.mp4

[Rygaa]

edit: there can also be flickering during click and drag when the selection starts with hidden markdown formatting:

I fixed this issue
https://github.com/user-attachments/assets/f28d5cee-e697-41b0-be63-d5071d1e8e49

I noticed one minor issue with selections, where when the markup reveals on mouseup, the selection is sometimes missing the markdown formatting characters (even though the selection covered the entire word):

I created a different issue for it #15788