[docs] Improve JSDoc

First seen in #68 (comment)

packages/grid/x-grid-modules/src/models/params/cellParams.ts

@@ -5,32 +5,33 @@ import { CellValue, RowData, RowModel } from '../rows';
  */
 export interface CellParams {
   /**
-   * the cell value
+   * The cell value.
    */
   value: CellValue;
   /**
-   * A function that let you get data from other columns
+   * A function that let you get data from other columns.
+   *
    * @param field
    */
   getValue: (field: string) => CellValue;
   /**
-   * The full set of data of the row that the current cell belongs to
+   * The full set of data of the row that the current cell belongs to.
    */
   data: RowData;
   /**
-   * The row model  of the row that the current cell belongs to
+   * The row model of the row that the current cell belongs to.
    */
   rowModel: RowModel;
   /**
-   * The column of the row that the current cell belongs to
+   * The column of the row that the current cell belongs to.
    */
   colDef: any;
   /**
-   * The row index of the row that the current cell belongs to
+   * The row index of the row that the current cell belongs to.
    */
   rowIndex: number;
   /**
-   * ApiRef that let you manipulate the grid
+   * ApiRef that let you manipulate the grid.
    */
   api: any;
 }
@@ -39,6 +40,7 @@ export interface CellParams {
  * Alias of CellParams.
  */
 export type ValueGetterParams = CellParams;
+
 /**
  * Alias of CellParams.
  */