mathlib3

e160cefe - chore(*): add mathlib4 synchronization comments (#19200)

chore(*): add mathlib4 synchronization comments (#19200) Regenerated from the [port status wiki page](https://github.com/leanprover-community/mathlib/wiki/mathlib4-port-status). Relates to the following files: * `algebra.continued_fractions.computation.terminates_iff_rat` * `category_theory.enriched.basic` * `category_theory.monoidal.internal.limits` * `field_theory.krull_topology` * `measure_theory.function.conditional_expectation.basic` * `measure_theory.function.conditional_expectation.condexp_L1` * `measure_theory.function.conditional_expectation.condexp_L2` * `measure_theory.function.conditional_expectation.indicator` * `measure_theory.function.conditional_expectation.real` * `number_theory.legendre_symbol.basic` * `number_theory.legendre_symbol.quadratic_char.basic` * `probability.conditional_expectation` * `probability.notation` * `probability.process.adapted` * `probability.process.filtration` * `probability.process.stopping`