Update fip-0016.md

[Tanisha-fil]

This PR updates FIP-0016 status to Rejected.

Reason: After community and core team discussions, it was agreed that while FIP-0016 offered flexibility for miners, it conflicted with Filecoin’s long-term goals around economic alignment, on-chain transparency, and scalability. Similar functionality can already be achieved via sector-sized self-deals, and successor proposals like FIP-0017 address related upgrade use cases in a protocol-aligned way.

Closing this proposal as no further action is planned.

Are you drafting a new FIP?

Please follow these guidelines to help ensure that your proposal is set up for success in the governance process.

Open a discussion topic

Changes to the Filecoin core protocol proceed through open discussion.
Please open a new discussion topic in the FIPs repository discussion board and outline you motivation and proposal.

The FIP format is suitable for specifying a concrete protocol change for implementation,
but your discussion post should describe more of the background and problem to be solved,
outline a range of approaches and their tradeoffs, and invite participants to explore other solutions.

Historically, failing to gain some community buy-in before submitting a FIP has often resulted in
rejected FIPs and much wasted effort.

Please use the template

Please draft your FIP by starting with an appropriate template file from templates directory.
Do not significantly change the header table format or section headings.

Don't claim a FIP number

FIP numbers are allocated by the FIP editors when a draft is ready to be merged into the master branch.
The editors coordinate to ensure allocations to in-flight drafts don't collide.
Please do not allocate yourself a FIP number.

Name your file fip-my_draft_title.md (replacing the suffix with an abbreviated title)
and leave "to be assigned" for the FIP number in the header table.
A FIP editor will either inform you of the appropriate number, or insert it themselves when merging.

Please add your FIP to the README

The top-level README.md file contains a table of all FIPs.
Please add yours there in the same PR that adds the FIP draft itself.
Use XXXX for the FIP number until it is assigned by an editor.

Delete this guidance and describe your FIP

Once you've followed the guidance above and are ready to submit your FIP draft,
please delete this text and replace it with a copy of the Abstract from your draft,
and a link to the relevant discussion forum topic.

[rvagg]

Do we have this reason documented somewhere other than in this issue? If it's public, it would be good to link to it in this PR thread at least so there's a constent trail.