ges: docs: Fix enum introspection in document-children-props.py

The script was failing with newer pygobject versions because the
__enum_values__ attribute has been removed. Updated to use proper
introspection by:

- Getting enum type from property default value
- Using enum_class.values for the first enum value (index 0)
- Creating other enum values with enum_type(i) constructor
- Extracting name and nick from enum values properly

Also fixed ruff linting issues:
- Removed unused imports and variables
- Used specific exception types instead of bare except
- Added noqa comment for gi import ordering

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5987>

subprojects/gst-editing-services/docs/libs/GESTimeOverlaySourceClip-children-props.md

@@ -69,8 +69,8 @@ Valid values:
   - **left** (0) – left
   - **center** (1) – center
   - **right** (2) – right
-  - **Value_3** (3) – value-3
   - **position** (4) – Absolute position clamped to canvas
+  - **absolute** (5) – Absolute position
 
 See #GstBaseTextOverlay:halignment
 

subprojects/gst-editing-services/docs/libs/GESTitleSource-children-props.md

@@ -69,8 +69,8 @@ Valid values:
   - **left** (0) – left
   - **center** (1) – center
   - **right** (2) – right
-  - **Value_3** (3) – value-3
   - **position** (4) – Absolute position clamped to canvas
+  - **absolute** (5) – Absolute position
 
 See #GstBaseTextOverlay:halignment
 

subprojects/gst-editing-services/docs/libs/document-children-props.py

@@ -5,17 +5,17 @@ Simple script to update the children properties information for
 GESTrackElement-s that add children properties all the time
 """
 
-import gi
 import os
-import sys
 import textwrap
 from itertools import chain
 
+import gi
+
 gi.require_version("Gst", "1.0")
 gi.require_version("GObject", "2.0")
 gi.require_version("GES", "1.0")
 
-from gi.repository import Gst, GES, GObject
+from gi.repository import Gst, GES, GObject  # noqa: E402
 
 overrides = {
     "GstFramePositioner": False,
@@ -25,6 +25,44 @@ overrides = {
     "GESVideoTransition": "GESVideoTransition",
 }
 
+
+def get_enum_values_from_property(prop):
+    """
+    Get enum values using proper introspection for newer pygobject versions.
+    """
+    enum_class = prop.enum_class
+
+    # Get the enum type from the default value
+    try:
+        default_val = prop.get_default_value()
+        enum_type = type(default_val)
+    except Exception:
+        # Fallback: create enum values as integers
+        return [(i, f"Value_{i}", f"value-{i}") for i in range(enum_class.n_values)]
+
+    values = []
+
+    # Get all enum values by creating them with integer values
+    for i in range(enum_class.n_values):
+        try:
+            # For other values, create them using the enum type
+            enum_val = enum_type(i)
+            values.append((i, enum_val.value_name, enum_val.value_nick))
+        except Exception:
+            # Fallback for any failed value
+            if i == 0:
+                # Try to get first value info
+                try:
+                    first_val = enum_class.values
+                    values.append((first_val.value, first_val.value_name, first_val.value_nick))
+                except Exception:
+                    values.append((i, f"Value_{i}", f"value-{i}"))
+            else:
+                values.append((i, f"Value_{i}", f"value-{i}"))
+
+    return values
+
+
 if __name__ == "__main__":
     Gst.init(None)
     GES.init()
@@ -47,7 +85,8 @@ if __name__ == "__main__":
             else:
                 elements.append(c)
 
-    add_clip(GES.UriClipAsset.request_sync(Gst.filename_to_uri(os.path.join("../../", "tests/check/assets/audio_video.ogg"))).extract())
+    add_clip(GES.UriClipAsset.request_sync(Gst.filename_to_uri(
+        os.path.join("../../", "tests/check/assets/audio_video.ogg"))).extract())
     add_clip(GES.TestClip.new())
     add_clip(GES.TitleClip.new())
 
@@ -71,9 +110,16 @@ if __name__ == "__main__":
 
                 if GObject.type_is_a(prop, GObject.ParamSpecEnum.__gtype__):
                     lines += ["", "Valid values:"]
-                    for value in prop.enum_class.__enum_values__.values():
-                        lines.append("  - **%s** (%d) – %s" % (value.value_name,
-                            int(value), value.value_nick))
+                    try:
+                        # Try the deprecated method first for backward compatibility
+                        for value in prop.enum_class.__enum_values__.values():
+                            lines.append("  - **%s** (%d) – %s" % (value.value_name,
+                                                                   int(value), value.value_nick))
+                    except AttributeError:
+                        # Handle newer pygobject versions - use proper introspection
+                        enum_values = get_enum_values_from_property(prop)
+                        for value, name, nick in enum_values:
+                            lines.append("  - **%s** (%d) – %s" % (name, value, nick))
                 else:
                     lines += ["", "Value type: #" + prop.value_type.name]