There is no "the relevant section" in the sense you want.
You're looking for an explicit statement of a thing which is never actually specifically called out. It's just that it's absolutely logically implied by all the other things.
Look, imagine that your GM declares that you can't use a longsword to hit opponents.
"But wait! It's a weapon."
"So?"
"Weapons can be used to attack."
"Maybe some weapons can. But I don't see anything saying you can attack anyone with a longsword."
Well, good luck fixing that one.
Enhancement bonuses apply to both attack rolls and damage. The enhancement bonus of a ranged weapon applies to its ammunition as well.
I was thinking this was maybe a result of the group being used to 2E, but no, it's actually even better for you there:
2nd Edition AD&D wrote:
Bow +1: This gives a +1 bonus to attack and damage rolls to arrows fired from it. If magical arrows are used, total the bonuses of both the bow and the arrows used. The type of bow found (composite, short, long, etc.) should be based on the circumstances of your campaign and the nature of the area. A nonmagical arrow fired from a magical bow is a nonmagical missile.
Anyway, Pathfinder rules for magic weapons
PRD wrote:
A magic weapon is enhanced to strike more truly and deliver more damage. Magic weapons have enhancement bonuses ranging from +1 to +5. They apply these bonuses to both attack and damage rolls when used in combat.
Note that "combat" does not mean "melee only". So, magic weapons apply to both attack and damage rolls.
PRD wrote:
Ranged Weapons and Ammunition: The enhancement bonus from a ranged weapon does not stack with the enhancement bonus from ammunition. Only the higher of the two enhancement bonuses applies.
Ammunition fired from a projectile weapon with an enhancement bonus of +1 or higher is treated as a magic weapon for the purpose of overcoming damage reduction. Similarly, ammunition fired from a projectile weapon with an alignment gains the alignment of that projectile weapon.
So there's no stacking, but the enhancement bonus from the ranged weapon definitely applies. You're just expected to be able to figure out that if you are using a ranged weapon, it doesn't suddenly use a special rule which isn't in print anywhere and never has been that I can find, which would have prevented it from applying to damage.
