text: Title: Form generation with enum has an bug
  Body: ### Checklist
  
  - [X] The bug is reproducible against the latest release or `master`.
  - [X] There are no similar issues or pull requests to fix it yet.
  
  ### Describe the bug
  
  I have model with enum. When I open edit view, none of the options in the html have the selected attribute.
  
  ### Steps to reproduce the bug
  
  ```python
  
  class CompanyPermissionEnum(enum.Enum):
      project_create = "project_create"
      project_read = "project_read"
      project_update = "project_update"
      
      
  class CompanyUserPermission(Base):
      ...
      permission = Column(
          Enum(CompanyPermissionEnum, name="company_permission"),
          nullable=False,
      )
  ```
  
  
  ### Expected behavior
  
  _No response_
  
  ### Actual behavior
  
  _No response_
  
  ### Debugging material
  
  _No response_
  
  ### Environment
  
  - python 3.9
  - sqlalchemy 1.4.31
  
  ### Additional context
  
  according to https://stackoverflow.com/a/51858425 I have fixed like this
  
  ```python
  
  def coerce_for_enum(enum):
      def coerce(name):
          if isinstance(name, enum):
              return name
          try:
              return enum[name]
          except KeyError:
              raise ValueError(name)
  
      return coerce
  
  
  class CustomModelConverter(ModelConverter):
      @converts("Enum")
      def conv_Enum(
          self, column: Column, field_args: dict, **kwargs: Any
      ) -> Field:
          field_args["choices"] = [(e, e) for e in column.type.enums]
          return SelectField(
              **field_args,
              coerce=coerce_for_enum(column.type.enum_class),
          )
  
  ```