Fix T79822: Custom preset casing not preserved

When adding a new preset the name would be converted to lower case and
then displayed in the interface in title case. This was confusing
because the name didn't reflect what was typed, and there are many cases
when the name shouldn't be forced into title case (like 8K UHDTV for
example).

This commit leaves the custom preset names in the original casing, and
removes the conversion of filenames to title case for preset lists.

Differential Revision: https://developer.blender.org/D10224

release/scripts/startup/bl_operators/presets.py

@@ -77,7 +77,7 @@ class AddPresetBase:
                 setattr(cls, attr, trans)
             return trans
 
-        name = name.lower().strip()
+        name = name.strip()
         name = bpy.path.display_name_to_filepath(name)
         trans = maketrans_init()
         # Strip surrounding "_" as they are displayed as spaces.
@@ -249,7 +249,7 @@ class ExecutePreset(Operator):
 
         # change the menu title to the most recently chosen option
         preset_class = getattr(bpy.types, self.menu_idname)
-        preset_class.bl_label = bpy.path.display_name(basename(filepath))
+        preset_class.bl_label = bpy.path.display_name(basename(filepath), title_case=False)
 
         ext = splitext(filepath)[1].lower()