DOC: Complete adding docstrings to Pydantic models

Also adds them to enums, and renames some classes to remove the
redundant `Enum` in the name or align with other names (i.e.
FMUSomething as opposed to FmuSomething).

Removing descriptions from the `Field(description="...")` also removes
these descriptions from the schema right now. However, with Pydantic 2.7
(when we are able to upgrade to it), moving these descriptions to
docstrings will add them back into the schema description. So this loss
of fidelity is temporary.

src/fmu/dataio/aggregation.py

@@ -11,7 +11,7 @@
 from . import _utils, dataio, types
 from ._logging import null_logger
 from ._metadata import generate_meta_tracklog
-from .datastructure.meta.enums import FmuContext
+from .datastructure.meta.enums import FMUContext
 from .providers.objectdata._provider import objectdata_provider_factory
 
 logger: Final = null_logger(__name__)
@@ -230,7 +230,7 @@ def _generate_aggrd_metadata(
         template["fmu"]["aggregation"]["id"] = self.aggregation_id
 
         # fmu.context.stage should be 'iteration'
-        template["fmu"]["context"]["stage"] = FmuContext.iteration.value
+        template["fmu"]["context"]["stage"] = FMUContext.iteration.value
 
         # next, the new object will trigger update of: 'file', 'data' (some fields) and
         # 'tracklog'.

src/fmu/dataio/dataio.py

@@ -28,7 +28,7 @@
 from .case import InitializeCase
 from .datastructure.configuration import global_configuration
 from .datastructure.meta import enums
-from .datastructure.meta.enums import FmuContext
+from .datastructure.meta.enums import FMUContext
 from .preprocessed import ExportPreprocessedData
 from .providers._fmu import FmuProvider, get_fmu_context_from_environment
 
@@ -662,15 +662,15 @@ def _validate_and_establish_fmucontext(self) -> None:
             self.fmu_context = None
 
         else:
-            self.fmu_context = FmuContext(self.fmu_context.lower())
+            self.fmu_context = FMUContext(self.fmu_context.lower())
             logger.info("FMU context is %s", self.fmu_context)
 
-        if self.preprocessed and self.fmu_context == FmuContext.realization:
+        if self.preprocessed and self.fmu_context == FMUContext.realization:
             raise ValueError(
                 "Can't export preprocessed data in a fmu_context='realization'."
             )
 
-        if self.fmu_context != FmuContext.case and env_fmu_context == FmuContext.case:
+        if self.fmu_context != FMUContext.case and env_fmu_context == FMUContext.case:
             warn(
                 "fmu_context is set to 'realization', but unable to detect "
                 "ERT runpath from environment variable. "
@@ -727,7 +727,7 @@ def _establish_rootpath(self) -> Path:
         )
 
         if self._fmurun:
-            assert isinstance(self.fmu_context, FmuContext)
+            assert isinstance(self.fmu_context, FMUContext)
             if casepath := FmuProvider(
                 fmu_context=self.fmu_context,
                 casepath_proposed=Path(self.casepath) if self.casepath else None,
@@ -747,7 +747,7 @@ def _establish_rootpath(self) -> Path:
         return self._pwd
 
     def _get_fmu_provider(self) -> FmuProvider:
-        assert isinstance(self.fmu_context, FmuContext)
+        assert isinstance(self.fmu_context, FMUContext)
         return FmuProvider(
             model=self.config.get("model"),
             fmu_context=self.fmu_context,

src/fmu/dataio/datastructure/_internal/internal.py

@@ -70,7 +70,7 @@ class ContentRequireSpecific(BaseModel):
 
 
 class AllowedContent(BaseModel):
-    content: Union[meta.enums.ContentEnum, Literal["unset"]]
+    content: Union[meta.enums.Content, Literal["unset"]]
     content_incl_specific: Optional[ContentRequireSpecific] = Field(default=None)
 
     @model_validator(mode="before")
@@ -81,7 +81,7 @@ def _validate_input(cls, values: dict) -> dict:
 
         if content in ContentRequireSpecific.model_fields and not content_specific:
             # 'property' should be included below after a deprecation period
-            if content == meta.enums.ContentEnum.property:
+            if content == meta.enums.Content.property:
                 property_warn()
             else:
                 raise ValueError(f"Content {content} requires additional input")
@@ -113,7 +113,7 @@ class FMUModelCase(BaseModel):
 
 
 class Context(BaseModel, use_enum_values=True):
-    stage: meta.enums.FmuContext
+    stage: meta.enums.FMUContext
 
 
 # Remove the two models below when content is required as input.
@@ -122,7 +122,7 @@ class UnsetContent(meta.content.Data):
 
     @model_validator(mode="after")
     def _deprecation_warning(self) -> UnsetContent:
-        valid_contents = [m.value for m in meta.enums.ContentEnum]
+        valid_contents = [m.value for m in meta.enums.Content]
         warnings.warn(
             "The <content> is not provided which will produce invalid metadata. "
             "It is strongly recommended that content is given explicitly! "
@@ -147,15 +147,15 @@ class DataClassMeta(JsonSchemaMetadata):
     # TODO: aim to use meta.FMUDataClassMeta as base
     # class and disallow creating invalid metadata.
     class_: Literal[
-        meta.enums.FMUClassEnum.surface,
-        meta.enums.FMUClassEnum.table,
-        meta.enums.FMUClassEnum.cpgrid,
-        meta.enums.FMUClassEnum.cpgrid_property,
-        meta.enums.FMUClassEnum.polygons,
-        meta.enums.FMUClassEnum.cube,
-        meta.enums.FMUClassEnum.well,
-        meta.enums.FMUClassEnum.points,
-        meta.enums.FMUClassEnum.dictionary,
+        meta.enums.FMUClass.surface,
+        meta.enums.FMUClass.table,
+        meta.enums.FMUClass.cpgrid,
+        meta.enums.FMUClass.cpgrid_property,
+        meta.enums.FMUClass.polygons,
+        meta.enums.FMUClass.cube,
+        meta.enums.FMUClass.well,
+        meta.enums.FMUClass.points,
+        meta.enums.FMUClass.dictionary,
     ] = Field(alias="class")
     fmu: Optional[FMUClassMetaData]
     masterdata: Optional[meta.Masterdata]