changed intent from out to inout

to support assignment of the same variable, i.e., `set=set`

Author: degawa

src/stdlib_bitsets.fypp

@@ -1170,8 +1170,8 @@ module stdlib_bitsets
 !! Version: experimental
 !!
 !! Used to define assignment for `bitset_large`.
-            type(bitset_large), intent(out) :: set1
-            type(bitset_large), intent(in)  :: set2
+            type(bitset_large), intent(inout) :: set1
+            type(bitset_large), intent(in)    :: set2
         end subroutine assign_large
 
     #:for k1 in INT_KINDS

src/stdlib_bitsets_large.fypp

@@ -91,8 +91,8 @@ contains
 
     pure module subroutine assign_large( set1, set2 )
 !     Used to define assignment for bitset_large
-        type(bitset_large), intent(out) :: set1
-        type(bitset_large), intent(in)  :: set2
+        type(bitset_large), intent(inout) :: set1
+        type(bitset_large), intent(in)    :: set2
 
         set1 % num_bits = set2 % num_bits
         allocate( set1 % blocks( size( set2 % blocks, kind=bits_kind ) ) )