Feat: activate always_modified plugin

plugins/__init__.py

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+from .always_modified import *

plugins/always_modified.py

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+"""
+If "modified" date/time is not defined in article metadata, fall back to the "created" date.
+"""
+
+from pelican import signals
+from pelican.contents import Content, Article
+
+def add_modified(content):
+    if not isinstance(content, Article):
+        return
+    
+    if not content.settings.get('ALWAYS_MODIFIED', False):
+        return
+
+    if hasattr(content, 'date') and not hasattr(content, 'modified'):
+        content.modified = content.date
+        content.locale_modified = content.locale_date
+    
+def register():
+    signals.content_object_init.connect(add_modified)

plugins/always_modified/README.md

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+# Always Modified
+
+Say you want to sort by modified date/time in a theme template, but not all
+your articles have modified date/timestamps explicitly defined in article
+metadata. This plugin facilitates that sorting by assuming the modified date
+(if undefined) is equal to the created date.
+
+## Usage
+
+1. Add `ALWAYS_MODIFIED = True` to your settings file.
+2. Now you can sort by modified date in your templates:
+
+    {% for article in articles|sort(reverse=True,attribute='modified') %}
+