Set ADD_ITEM_EQEFFECT defaults to target 1 and timing 2

[4Luke4]

Summary

• change the built-in ADD_ITEM_EQEFFECT function defaults from target = 0 and timing = 0 to target = 1 and timing = 2
• document the function-specific defaults in doc/base.tex
• clarify the general macro/function defaults documentation so that function-specific exceptions are documented with the corresponding function
• add a release-note entry for version 251

Rationale

ADD_ITEM_EQEFFECT adds an equipping effect to an item. When callers omit the target and timing parameters, the built-in patch-function wrapper should supply the appropriate equipping-effect defaults:

• target = 1 (Self)
• timing = 2 (Instant/While equipped)

The change is intentionally limited to DEFINE_PATCH_FUNCTION ~ADD_ITEM_EQEFFECT~.

The shared ADD_ITEM_EQEFFECT macro remains unchanged because it is also used by ADD_SPELL_CFEFFECT. Consequently, ADD_SPELL_CFEFFECT retains its existing target = 0 and timing = 0 defaults, and the shared macro's field-writing and cleanup behavior is unaffected.

Validation

• verified that ADD_ITEM_EQEFFECT defaults to target = 1 and timing = 2
• verified that ADD_SPELL_CFEFFECT remains at target = 0 and timing = 0
• verified that the shared ADD_ITEM_EQEFFECT macro's field writes and cleanup values remain unchanged
• verified all corresponding documentation references
• verified the version 251 release-note entry
• ran git diff --check
• successfully built WeiDU on Ubuntu 22.04 with OCaml 4.14.2, ocaml-option-default-unsafe-string, and Elkhound 1.0.3