dep: minor docstring updates for dep classes

Author: radhermit

src/pkgcraft/dep/base.pyx

@@ -7,7 +7,7 @@ from .set cimport _IntoIterFlatten, _IntoIterRecursive
 
 @cython.final
 cdef class Dep(_IndirectInit):
-    """Dependency restriction."""
+    """Dependency object."""
 
     @staticmethod
     cdef Dep from_ptr(C.Dep *ptr):

src/pkgcraft/dep/set.pyx

@@ -10,7 +10,7 @@ from ..error import PkgcraftError
 
 
 cdef class DepSet(_IndirectInit):
-    """Dependency set of objects."""
+    """Set of dependency objects."""
 
     @staticmethod
     cdef DepSet from_ptr(C.DepSet *ptr, DepSet obj=None):