Fixing title of the optimization

Author: FranciscoThiesen

cppcon2025/cppcon_2025_slides.md

@@ -969,7 +969,7 @@ From neuroscience: systematically remove parts to understand function
 
 1. **Consteval**: Compile-time field name processing
 2. **SIMD String Escaping**: Vectorized character checks
-3. **Fast Integer Conversion**: Optimized number serialization
+3. **Fast Digit Counting**: Optimized digit count
 4. **Branch Prediction Hints**: CPU pipeline optimization
 5. **Buffer Growth Strategy**: Smart memory allocation