new exp_fit with s * () + dual and triple #765

All 379 tests pass, 3 skipped in 46s

382 tests +382 379 ✔️ +379 46s ⏱️ +46s
    1 suites +    1     3 💤 +    3
    1 files +    1     0 ❌ ±    0

Results for commit 89e085a. ± Comparison against earlier commit 11360eb.