UI: Fix a few typos

- "Acion Slot" -> "Action": typo.
- "Specifies the input node used the created zone" -> "by the created
  zone": typo.
- "No reference available {!r}, Update..." -> "update": lower case.
- "uninitialized file-list" -> "Uninitialized": sentence case.

Some issues reported by Alexandr Fatih.

Pull Request: https://projects.blender.org/blender/blender/pulls/148265

scripts/addons_core/rigify/operators/action_layers.py

@@ -107,7 +107,7 @@ class ActionSlot(PropertyGroup, ActionSlotBase):
         return str(action_slot.handle)
 
     action_slot_ui: StringProperty(
-        name="Acion Slot",
+        name="Action Slot",
         description="Slot of the Action to use for the Action Constraints",
         # These callbacks let us store the action slot's `handle` property
         # under the hood (which is unique and never changes), while acting

scripts/startup/bl_operators/node.py

@@ -667,12 +667,12 @@ class NODE_OT_add_zone(NodeAddZoneOperator, Operator):
 
     input_node_type: StringProperty(
         name="Input Node",
-        description="Specifies the input node used the created zone",
+        description="Specifies the input node used by the created zone",
     )
 
     output_node_type: StringProperty(
         name="Output Node",
-        description="Specifies the output node used the created zone",
+        description="Specifies the output node used by the created zone",
     )
 
     add_default_geometry_link: BoolProperty(
@@ -689,12 +689,12 @@ class NODE_OT_swap_zone(ZoneOperator, NodeSwapOperator, Operator):
 
     input_node_type: StringProperty(
         name="Input Node",
-        description="Specifies the input node used the created zone",
+        description="Specifies the input node used by the created zone",
     )
 
     output_node_type: StringProperty(
         name="Output Node",
-        description="Specifies the output node used the created zone",
+        description="Specifies the output node used by the created zone",
     )
 
     add_default_geometry_link: BoolProperty(

scripts/startup/bl_operators/wm.py

@@ -1342,7 +1342,7 @@ class WM_OT_doc_view_manual(Operator):
             self.report(
                 {'WARNING'},
                 rpt_("No reference available {!r}, "
-                     "Update info in '_rna_manual_reference.py' "
+                     "update info in '_rna_manual_reference.py' "
                      "or callback to bpy.utils.manual_map()").format(self.doc_id)
             )
             return {'CANCELLED'}