Store multiple -contains arguments (OR default).

Allow multiple occurrences of the -contains argument
to be stored in a list. Previously, only the last occurrence was
considered. Additionally, the behavior has been modified to default to
OR logic, meaning that if multiple -contains arguments are provided,
entries matching any of them will be included in the results.

jrnl/args.py

@@ -265,6 +265,7 @@ def parse_args(args: list[str] = []) -> argparse.Namespace:
     reading.add_argument(
         "-contains",
         dest="contains",
+        action="append",
         metavar="TEXT",
         help="Show entries containing specific text (put quotes around text with "
         "spaces)",

jrnl/journals/Journal.py

@@ -246,7 +246,7 @@ class Journal:
         exclude_starred=False,
         exclude_tagged=False,
         strict=False,
-        contains=None,
+        contains=[],
         exclude=[],
     ):
         """Removes all entries from the journal that don't match the filter.
@@ -276,7 +276,7 @@ class Journal:
             return 0 < len([tag for tag in tags if tag in excluded_tags])
 
         if contains:
-            contains_lower = contains.casefold()
+            contains_lower = [substring.casefold() for substring in contains]
 
         # Create datetime object for comparison below
         # this approach allows various formats
@@ -298,8 +298,11 @@ class Journal:
             and (
                 not contains
                 or (
-                    contains_lower in entry.title.casefold()
-                    or contains_lower in entry.body.casefold()
+                    any(
+                        substring in entry.title.casefold() 
+                        or substring in entry.body.casefold()
+                        for substring in contains_lower
+                    )
                 )
             )
         ]