feat(bitbucket): massage markdown for collapsible sections section

[setchy]

Changes

Massage markdown for Detected Dependencies and Vulnerabilities sections dependencies sections within Bitbucket issues.

• Use > markdown block quote
• Use nested unordered lists
• Format package files as preformatted code

Modeled to to be as close to the GitHub formatting as Bitbucket will support

Context

Before	After

Please select one of the following:

• This closes an existing Issue, Closes: #
• This doesn't close an Issue, but I accept the risk that this PR may be closed if maintainers disagree with its opening or implementation

AI assistance disclosure

Did you use AI tools to create any part of this pull request?

Please select one option and, if yes, briefly describe how AI was used (e.g., code, tests, docs) and which tool(s) you used.

• No — I did not use AI for this contribution.
• Yes — minimal assistance (e.g., IDE autocomplete, small code completions, grammar fixes).
• Yes — substantive assistance (AI-generated non‑trivial portions of code, tests, or documentation).
• Yes — other (please describe):

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests, but ran on a real repository, or
• Both unit tests + ran on a real repository

The public repository:

[setchy]

Converting to draft - need to add a unit test for the Vulnerabilities section to make sure this is also parsed correctly