IMP | Retired the old stable matlab documentation system derived from the M2Html

Author: pritkc

doc/sphinx/source/api/matlab/index.md

@@ -59,19 +59,12 @@ intros/gettingstarted.rst
 Building Documentation <intros/doc_readme_wrapper.md>
 ```
 
-```{toctree}
-:maxdepth: 3
-:caption: API Reference
-
-api/cpp/index
-Matlab/ Octave <api/matlab/index.md>
-```
-
 ```{toctree}
 :maxdepth: 4
-:caption: MATLAB API (Beta)
+:caption: API Reference
 
-Matlab/ Octave (beta) <api/matlab/index-beta.rst>
+C++ <api/cpp/index>
+Matlab/ Octave <api/matlab/index-beta.rst>
 ```
 
 ```{toctree}