[UX] tab1_inputs.py: British spelling (optimization -> optimisation)

tabs/tab1_inputs.py

@@ -749,7 +749,7 @@ def render_tab(cost_sliders):
     st.markdown('<p class="objective_title">OBJECTIVE</p>', unsafe_allow_html=True)
     st.markdown(
         '<p class="text_with_border">This section lets you define the <strong>total available '
-        'quantities of each resource</strong> for the optimization model.<br>'
+        'quantities of each resource</strong> for the optimisation model.<br>'
         'Availability is per <strong>year</strong> (rate) for the specific year the portfolio is being estimated, for example 2030, or 2050</p>',
         unsafe_allow_html=True,
     )
@@ -814,7 +814,7 @@ def render_tab(cost_sliders):
             if not display_rlist:
                 st.caption(
                     "No standard resource to display for this group. "
-                    "Add a specific resource below to include it in the optimization."
+                    "Add a specific resource below to include it in the optimisation."
                 )
 
             cols = st.columns(4)