remove modelsummary_wide from README in favor of group

Author: vincentarelbundock

README.md

@@ -17,7 +17,6 @@ The tables and plots produced by `modelsummary` are beautiful and highly customi
 
 1. Model Summary
     - `modelsummary`: Regression tables with side-by-side models.
-    - `modelsummary_wide`: Regression tables for categorical response models or grouped coefficients.
     - `modelplot`: Coefficient plots.
 2. Data Summary
     - `datasummary`: Powerful tool to create (multi-level) cross-tabs and data summaries.