Update output file fields docs to correctly define Grid_Size (#526)

Co-authored-by: Bhardwaj, Gopesh <Gopesh.Bhardwaj@amd.com>

source/docs/how-to/using-rocprofv3.rst

@@ -1528,16 +1528,16 @@ The following table lists the various fields or the columns in the output CSV fi
     - The group segment memory required by a workgroup in bytes. This does not include any dynamically allocated group segment memory that may be added when the kernel is dispatched.
 
   * - Workgroup_Size
-    - Size of the workgroup as declared by the compute shader.
+    - The total number of work-items (or, threads) in each workgroup (or, block) launched as part of the kernel dispatch. In HIP, this is equivalent to the total block size.
 
   * - Workgroup_Size_n
     - Size of the workgroup in the nth dimension as declared by the compute shader, where n = X, Y, or Z.
 
   * - Grid_Size
-    - Number of thread blocks required to launch the kernel.
+    - The total number of work-items (or, threads) launched as a part of the kernel dispatch. In HIP, this is equivalent to the total grid size multiplied by the total workgroup (or, block) size.
 
   * - Grid_Size_n
-    - Number of thread blocks in the nth dimension required to launch the kernel, where n = X, Y, or Z.
+    - Number of work-items (or, threads) in the nth dimension required to launch the kernel, where n = X, Y, or Z.
 
   * - LDS_Block_Size
     - Thread block size for the kernel's Local Data Share (LDS) memory.