Fix sentence fragment (#29431)

Move whereas clause into subordinate position to avoid sentence fragment.

doc/src/manual/types.md

@@ -1123,9 +1123,9 @@ Of course, this depends on what `Int` is aliased to -- but that is predefined to
 type -- either [`Int32`](@ref) or [`Int64`](@ref).
 
 (Note that unlike `Int`, `Float` does not exist as a type alias for a specific sized
-[`AbstractFloat`](@ref). Unlike with integer registers, the floating point register sizes
-are specified by the IEEE-754 standard. Whereas the size of `Int` reflects the size of a
-native pointer on that machine.)
+[`AbstractFloat`](@ref). Unlike with integer registers, where the size of `Int`
+reflects the size of a native pointer on that machine, the floating point register sizes
+are specified by the IEEE-754 standard.)
 
 ## Operations on Types