[IMP] fields: remove '_id(s)' from the label

For autogenerated labels.
Use title instead of capitalize to get every word with a capital letter.

Closes #12769

addons/base_import/tests/test_base_import.py

@@ -99,7 +99,7 @@ class TestO2M(BaseImportCase):
         self.assertEqualFields(self.get_fields('o2m'), make_field(field_type='one2many', fields=[
             ID_FIELD,
             # FIXME: should reverse field be ignored?
-            {'id': 'parent_id', 'name': 'parent_id', 'string': 'Parent id', 'type': 'many2one', 'required': False, 'fields': [
+            {'id': 'parent_id', 'name': 'parent_id', 'string': 'Parent', 'type': 'many2one', 'required': False, 'fields': [
                 {'id': 'parent_id', 'name': 'id', 'string': 'External ID', 'required': False, 'fields': [], 'type': 'id'},
                 {'id': 'parent_id', 'name': '.id', 'string': 'Database ID', 'required': False, 'fields': [], 'type': 'id'},
             ]},

odoo/fields.py

@@ -470,7 +470,10 @@ class Field(object):
 
         if not self.string and not self.related:
             # related fields get their string from their parent field
-            self.string = name.replace('_', ' ').capitalize()
+            self.string = (
+                name[:-4] if name.endswith('_ids') else
+                name[:-3] if name.endswith('_id') else name
+            ).replace('_', ' ').title()
 
         # self.default must be a callable
         if self.default is not None: