docs(tables): clarify Delete/Backspace clears all columns in checkbox mode

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: waleedlatif1

apps/docs/content/docs/en/tables/index.mdx

@@ -116,7 +116,7 @@ All shortcuts work when the table is focused and no cell is being edited.
 | `Mod` + `C` | Copy selected cells |
 | `Mod` + `X` | Cut selected cells |
 | `Mod` + `V` | Paste |
-| `Delete` / `Backspace` | Clear selected cell contents |
+| `Delete` / `Backspace` | Clear selected cells (all columns when using checkbox selection) |
 
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