refine the docstring a bit

Author: aviatesk

base/experimental.jl

@@ -375,18 +375,20 @@ non-overlayed method call.
 
 More formally, when evaluating a generic function call ``f(x)`` at a specific world age
 ``i``, if a regular method call ``fᵢ(x)`` is redirected to an overlay method call ``fᵢ′(x)``
-defined by this macro, it must be ensured that ``fᵢ(x) ≡ fᵢ′(x)``.
+defined by this macro, ``fᵢ(x)`` and ``fᵢ′(x)`` are considered `:consistent` if the following
+conditions are met:
+- If `fᵢ(x)` returns a value `y`, then `fᵢ′(x)` also returns some value `yᵢ`, and `y ≡ yᵢ` holds.
+- If `fᵢ(x)` throws an exception, then `fᵢ′(x)` also throws some exception.
 
 For a detailed definition of `:consistent`-cy, consult the corresponding section in
 [`Base.@assume_effects`](@ref).
 
 !!! note
     Note that the requirements for `:consistent`-cy include not only that the return values
-    are egal, but also that the manner of termination is the same.
-    However, it's important to aware that when they throw exceptions, the exceptions
-    themselves don't necessarily have to be egal as explained in the note of `:consistent`.
-    In other words, if ``fᵢ(x)`` throws an exception, ``fᵢ′(x)`` is required to also throw
-    one, but the exact exceptions may differ.
+    are egal, but also that the manner of termination is the same. However, it's important
+    to aware that when they throw exceptions, the exceptions themselves don't necessarily
+    have to be egal. In other words, if ``fᵢ(x)`` throws an exception, ``fᵢ′(x)`` is
+    required to also throw one, but the exact exceptions may differ.
 
 !!! note
     Please note that the `:consistent`-cy requirement applies not to method itself but to