rest/rpc: use more util::Join #32942

1. 
   stickies-v commented at 5:11 pm on July 10, 2025: contributor

   There are a few places in the RPC and REST code where we manually join multiple items into a string. This PR removes a bunch of that logic and replaces it with util::Join. To minimize unnecessary container allocations and simplify implementations, the first commit slightly refactors util::Join so it can subsequently be used with range adaptors.
2. util: make Join compatible with ranges

   By using a forwarding reference for `container`, the function can
   be used with range adaptors that produce views that are not iterable
   when const.

   c2bb73708a
3. rest: make rf_names a map to simplify code

   As a map, we can use views and util::Join on it to avoid duplicating
   logic.

   31bbaab9f1
4. 
   DrahtBot commented at 5:11 pm on July 10, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/32942.

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5. rpc: use more util::Join

   Use Join where we manually concatenated before, or use ranges to
   simplify the code.

   e68a4ba976
6. stickies-v force-pushed on Jul 10, 2025
7. DrahtBot added the label CI failed on Jul 10, 2025
8. 
   DrahtBot commented at 8:20 pm on July 10, 2025: contributor

   🚧 At least one of the CI tasks failed. Task tidy: https://github.com/bitcoin/bitcoin/runs/45741536315 LLM reason (✨ experimental): clang-tidy detected errors related to recursive call chains, causing the CI to fail.

   Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

   • Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

   • A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

   • An intermittent issue.

   Leave a comment here, if you need help tracking down a confusing failure.

9. 
   w0xlt commented at 8:42 pm on July 10, 2025: contributor

   Code Review ACK https://github.com/bitcoin/bitcoin/pull/32942/commits/e68a4ba976af59dfd15e3aa432e1ce80e7d21083
10. DrahtBot removed the label CI failed on Jul 11, 2025

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stickies-v DrahtBot w0xlt