docs: Fixed a couple errors in the Technical Specifications. (#9340)

These seemed like copy paste errors in their contexts.

docs/source/techspecs/memory.rst

@@ -197,7 +197,7 @@ that the lookup can be expensive, prefer finders instead.
 
 .. code-block:: C++
 
-    class memory_bank {
+    class memory_region {
         u8 *base();
         u8 *end();
         u32 bytes() const;

docs/source/techspecs/object_finders.rst

@@ -239,7 +239,7 @@ the object finders in the device class (with all distractions removed):
         }
 
         sbus_device(machine_config const &mconfig, char const *tag, device_t *owner, u32 clock) :
-            device_t(mconfig, type, tag, owner, clock),
+            device_t(mconfig, SBUS, tag, owner, clock),
             device_memory_interface(mconfig, *this),
             m_maincpu(*this, finder_base::DUMMY_TAG),
             m_type1space(*this, finder_base::DUMMY_TAG, -1)