docs: fix terminal directives

[jahn-junior]

Note that I did not assess the quality or necessity of any of these terminal directives. This PR is only a stopgap to get everything rendering correctly until I complete CHARMCRAFT-684 next pulse.

---

• I've followed the contribution guidelines.
• I've signed the CLA.
• I've successfully run make lint && make test.
• I've added or updated any relevant documentation.
• In documents I changed, I added a meta description if one was missing.
• I've updated the relevant release notes.

[jahn-junior]

These will get merged into a single terminal session once we bump the sphinx-terminal version.

[Copilot]

Pull request overview

Stopgap documentation update to make terminal examples render correctly under the sphinx_terminal Sphinx extension, primarily by converting code-block command/output pairs into .. terminal:: blocks and marking output-only snippets.

Changes:

• Replaced several .. code-block:: bash + .. terminal:: sequences with single .. terminal:: blocks that include both command and output.
• Added :output-only: to terminal blocks that show output without input.
• Adjusted a few doc examples (including comment formatting in manage-channels) as part of fixing rendering issues.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
docs/howto/pack-a-hooks-based-charm-with-charmcraft.rst	Converts command/output examples to .. terminal:: blocks for consistent rendering.
docs/howto/manage-web-app-charms/use-web-app-charm.rst	Marks a terminal snippet as output-only to render as plain output.
docs/howto/manage-web-app-charms/configure-web-app-charm.rst	Adds an output-only terminal block for expected results.
docs/howto/manage-the-current-charmhub-user.rst	Converts login example to a terminal block with command + output.
docs/howto/manage-revisions.rst	Uses terminal blocks for command + output and marks an output-only excerpt.
docs/howto/manage-resources.rst	Consolidates upload examples into terminal blocks containing command + output.
docs/howto/manage-extensions.rst	Converts several dropdown examples to terminal blocks and adds output-only metadata.
docs/howto/manage-charms.rst	Updates multiple lifecycle examples in dropdowns to use terminal blocks.
docs/howto/manage-charmcraft.rst	Converts macOS and Multipass examples to terminal blocks (including user/host options).
docs/howto/manage-channels.rst	Marks channel table as output-only and changes how a hidden explanatory block is represented.

Comments suppressed due to low confidence (2)

docs/howto/manage-extensions.rst:62

• This .. terminal:: is intended to be part of the preceding dropdown example, but it’s currently less-indented than the dropdown body, so it will be parsed outside the dropdown and may render incorrectly.

  .. terminal::

docs/howto/manage-extensions.rst:112

• Within this dropdown, the .. terminal:: directive needs to be indented to the dropdown body level; otherwise it will be parsed outside the dropdown and can break the structure of the page.

  .. terminal::