docs(multiple): small accessibility typos (#23595)

(cherry picked from commit 67f88d3)

Author: literalpie

src/material/dialog/dialog.md

@@ -155,7 +155,7 @@ You can control which elements are tab stops with the `tabindex` attribute
 `MatDialog` creates modal dialogs that implements the ARIA `role="dialog"` pattern by default.
 You can change the dialog's role to `alertdialog` via `MatDialogConfig`.
 
-You should provide a an accessible label to this root dialog element by setting the `ariaLabel` or
+You should provide an accessible label to this root dialog element by setting the `ariaLabel` or
 `ariaLabelledBy` properties of `MatDialogConfig`. You can additionally specify a description element
 ID via the `ariaDescribedBy` property of `MatDialogConfig`.
 

src/material/table/table.md

@@ -380,7 +380,7 @@ When using the `multiTemplateDataRows` directive to support multiple rows for ea
 By default, `MatTable` applies `role="table"`, assuming the table's contains primarily static
 content. You can change the role by explicitly setting `role="grid"` or `role="treegrid"` on the
 table element. While changing the role will update child element roles, such as changing
-`role="cell"` to `role="gridcell"`, this not _not_ apply additional keyboard input handling or
+`role="cell"` to `role="gridcell"`, this does _not_ apply additional keyboard input handling or
 focus management to the table.
 
 Always provide an accessible label for your tables via `aria-label` or `aria-labelledby` on the