doc: write overview on slab tab in tcm ui

Author: maryiaLichko

doc/tooling/tcm/tcm_ui_overview.rst

@@ -209,7 +209,7 @@ Each slab block’s size in the visualization reflects the total memory allocate
 the more memory allocated, the larger the visual representation.
 
 .. image:: _images/tcm_ui_slabs.png
-   :width: 700px
+   :width: 900px
 
 The overall fill percentage for a cache class is calculated using: