docs: add docstring to docs

DhairyaLGandhi · DhairyaLGandhi · commit 0bbf1e1f2a16 · 2025-08-11T20:14:23.000+05:30
diff --git a/docs/src/API/model_building.md b/docs/src/API/model_building.md
@@ -226,6 +226,7 @@ change_independent_variable
 add_accumulations
 noise_to_brownians
 convert_system_indepvar
+ModelingToolkit.subset_tunables
 ```
 
 ## Hybrid systems
