Update index.html CO2e unit

Update the x-label caption from "kg CO_2/m^3" to "kg CO_2e/m^3".

Author: JuliusatMeta

docs/index.html

@@ -219,7 +219,7 @@ <h3 class="ingredient-insight-title">Ingredient Insight</h3>
         <h2>Predicted Strength Curve</h2>
         <canvas id="curve-canvas" aria-label="Predicted concrete strength curve over curing time"></canvas>
         <div class="readouts" id="readouts">
-          <div>GWP: <span class="value" id="gwp-value">–</span> <span class="unit" id="gwp-unit">kg CO₂/m³</span></div>
+          <div>GWP: <span class="value" id="gwp-value">–</span> <span class="unit" id="gwp-unit">kg CO₂e/m³</span></div>
           <div>Cost: <span class="value" id="cost-value">–</span> <span id="cost-uncertainty"></span> <span class="unit" id="cost-unit">$/m³</span></div>
           <div class="wb-readout">W/B: <span class="value" id="wb-value">–</span></div>
           <!-- TODO: Add Slump readout once model/slump.json is available. -->