Remove investments from graph

Investments are not normally reported on the receiving end in
transaction logs, and they introduce too much visual noise in monthly
expense graphs. As such they will later appear in relevant invesment
graphs, but are removed for now from the available choices.

categories.yaml

@@ -49,6 +49,9 @@ Entertainment:
     - cinema
     - steam
 
+Investment:
+  group: investment
+
 Pets:
   group: required
 

pfbudget/graph.py

@@ -49,9 +49,13 @@ def monthly(db: DBManager, start: dt.date = dt.date.min, end: dt.date = dt.date.
         [
             [-groups[group] for _, groups in monthly_transactions]
             for group in pfbudget.categories.groups
-            if group != "income"
+            if group != "income" and group != "investment"
+        ],
+        labels=[
+            group
+            for group in pfbudget.categories.groups
+            if group != "income" and group != "investment"
         ],
-        labels=[group for group in pfbudget.categories.groups if group != "income"],
     )
     plt.legend(loc="upper left")
     plt.tight_layout()
@@ -103,11 +107,13 @@ def discrete(db: DBManager, start: dt.date = dt.date.min, end: dt.date = dt.date
             [-categories[category] for _, categories in monthly_transactions]
             for category in pfbudget.categories.categories
             if category not in pfbudget.categories.groups["income"]
+            and category not in pfbudget.categories.groups["investment"]
         ],
         labels=[
             category
             for category in pfbudget.categories.categories
             if category not in pfbudget.categories.groups["income"]
+            and category not in pfbudget.categories.groups["investment"]
         ],
     )
     plt.legend(loc="upper left")