Mycorrhiza Wiki 1.9.0

This is an important update, both introducing new features, and
breaking older stuff, while also fixing some bugs.

This update introduces categories, a new means of organizing
hyphae, in addition to links/backlinks and hypha nesting.
Starting with this update, you are no longer encouraged to use
hypha nesting. In fact, the sibling sidebar is disabled by default
now, effectively discouraging it. You can enable it, if your wiki
heavily depends on it, though.

https://mycorrhiza.wiki/hypha/release/1.9

Timur Ismagilov (50):
      Docker: Delete the line
      Siblings: Disable the sidebar by default
      Break a lot of stuff
      Break a lot of stuff
      Play around with package shroom
      Make mimetype.FromExtension case-insensitive
      Move hyphae.Iteration to a separate package
      Remove some unused stuff
      Backlinks: Fix backlinks for media and empty hyphae
      Rename attachment to media
      Views: Reimplement the topics sidebar
      Update robots.txt
      Experiment № 2. Reimplement AboutHTML
      Return ui.about_title
      Experiment № 3. QTPL+l10nEntry
      Fix the bug with renaming
      Fix the bug with deletion
      Categories: Draft the API for categories package
      Categories: Show pre-populated categories
      Categories: Implement category pages
      Categories: Refactor a little
      Categories: Add addition to/removal from categories
      Categories: Save to disk after changes
      Categories: Sanitize names before processing
      Categories: Add category list
      Categories: Add category list link to the top bar
      L10n experiment no. 6 (?)
      Recent changes: Get rid of ? in a circle
      API: Get rid of *-json URLs
      Views: Drop the *HTML suffix
      Categories: Style the categories card
      Categories: Localize the categories card
      Categories: Perform l10n tricks
      Categories: Place the categories card better on two-column layout
      Admin: Port /admin/ to the new template approach
      Categories: Do not let anons add to/remove from categories
      Categories: Do not let anons add to/remove from categories
      Categories: Make the lists look more like Mycorrhiza
      Move mycorrhiza.1 to help directory
      Change version to 1.9.0
      Categories: Write docs
      Update Go version
      Move sr.ht repo from handlerug to bouncepaw
      Remove #mycorrhiza-ru
      Categories: Make /category/ and /category the same
      Categories: Ignore empty hypha names and cat names in requests
      Categories: Clean up deleted category records
      Add shortcut for backlinks
      Mycomarkup: Update to v3.6.3
      Update README.md

Umar Getagazov (8):
      Update README
      Add mycorrhiza.1 man page
      Update Makefile for ease of packaging
      Makefile: fix go build invocation
      Use sbin instead of bin
      Makefile: forcefully disable cgo
      Revert "Use sbin instead of bin"
      primitive-diff: validate input