show_log: support names 'last' and 'last-x' in path

Co-authored-by: manor-tile <159947643+manor-tile@users.noreply.github.com>

share/actionsmap.yml

@@ -1976,7 +1976,7 @@ log:
                 - display
             arguments:
                 path:
-                    help: Log file which to display the content
+                    help: Log file which to display the content, or 'last' or 'last-X' to get the log in last-X position
                 -n:
                     full: --number
                     help: Number of lines to display

src/log.py

@@ -173,6 +173,16 @@ def log_show(
         share
     """
 
+    match_path = re.match(r"last(?:-(?P<position>[0-9]{1,6}))?$", path)
+
+    if match_path:
+        if match_path.group("position") == None:
+            position = 1
+        else:
+            position = int(match_path.group("position")) + 1
+        logs = log_list()
+        path = list(logs["operation"])[-position]["path"]
+
     if share:
         filter_irrelevant = True