feat: add orElse combinator to Sym.Simp.Simproc

[wkrozowski]

This PR adds orElse combinator to simprocs of Sym.Simp.

[ghost]

Mathlib CI status (docs):

• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 892cbe22f836cca3f30ec8e6828a9cc8acffaa67 --onto 9e18eea271d89f8744f0d455ddcc72436a41739e. You can force Mathlib CI using the force-mathlib-ci label. (2026-01-29 18:05:08)

[leanprover-bot]

Reference manual CI status:

• ❗ Reference manual CI will not be attempted unless your PR branches off the nightly-with-manual branch. Try git rebase 892cbe22f836cca3f30ec8e6828a9cc8acffaa67 --onto 42a0e9245300da6b3d971fa0033d726bb8e11cc3. You can force reference manual CI using the force-manual-ci label. (2026-01-29 18:05:10)