Update the input mapping system to not dispatch both a matched KeyDown and KeyDownNoRepeat

For example, if we update `input_mapping.rs` like so:

```diff
- entry!(KeyDown(KeyA); action_dispatch=ToolMessage::ActivateToolPath),
+ entry!(KeyDownNoRepeat(KeyA); action_dispatch=ToolMessage::ActivateToolPath),
```

Then CtrlA will fire both the selection of all layers...

```
entry!(KeyDown(KeyA); modifiers=[Accel], action_dispatch=DocumentMessage::SelectAllLayers),
```

...as well as the change to the Path tool, since one gets matched on `KeyDown` and another on `KeyDownNoRepeat`. If both were `KeyDown` or `KeyDownNoRepeat`, only one would match. But currently, both are matching, and we only want one to match.

After implementing this fix, the following mappings should be changed from `KeyDown` to `KeyDownNoRepeat`:

Mappings to change

```
// TransformLayerMessage
entry!(KeyDown(KeyX); action_dispatch=TransformLayerMessage::ConstrainX),
entry!(KeyDown(KeyY); action_dispatch=TransformLayerMessage::ConstrainY),

// PathToolMessage
entry!(KeyDown(KeyG); action_dispatch=PathToolMessage::GRS { key: KeyG }),
entry!(KeyDown(KeyR); action_dispatch=PathToolMessage::GRS { key: KeyR }),
entry!(KeyDown(KeyS); action_dispatch=PathToolMessage::GRS { key: KeyS }),

// PenToolMessage
entry!(KeyDown(KeyG); action_dispatch=PenToolMessage::GRS { grab: KeyG, rotate: KeyR, scale: KeyS }),
entry!(KeyDown(KeyR); action_dispatch=PenToolMessage::GRS { grab: KeyG, rotate: KeyR, scale: KeyS }),
entry!(KeyDown(KeyS); action_dispatch=PenToolMessage::GRS { grab: KeyG, rotate: KeyR, scale: KeyS }),

// ToolMessage
entry!(KeyDown(KeyV); action_dispatch=ToolMessage::ActivateToolSelect),
entry!(KeyDown(KeyZ); action_dispatch=ToolMessage::ActivateToolNavigate),
entry!(KeyDown(KeyI); action_dispatch=ToolMessage::ActivateToolEyedropper),
entry!(KeyDown(KeyT); action_dispatch=ToolMessage::ActivateToolText),
entry!(KeyDown(KeyF); action_dispatch=ToolMessage::ActivateToolFill),
entry!(KeyDown(KeyH); action_dispatch=ToolMessage::ActivateToolGradient),
entry!(KeyDown(KeyA); action_dispatch=ToolMessage::ActivateToolPath),
entry!(KeyDown(KeyP); action_dispatch=ToolMessage::ActivateToolPen),
entry!(KeyDown(KeyN); action_dispatch=ToolMessage::ActivateToolFreehand),
entry!(KeyDown(KeyL); action_dispatch=ToolMessage::ActivateToolLine),
entry!(KeyDown(KeyM); action_dispatch=ToolMessage::ActivateToolRectangle),
entry!(KeyDown(KeyE); action_dispatch=ToolMessage::ActivateToolEllipse),
entry!(KeyDown(KeyY); action_dispatch=ToolMessage::ActivateToolPolygon),
entry!(KeyDown(KeyB); action_dispatch=ToolMessage::ActivateToolBrush),

// DocumentMessage
entry!(KeyDown(Space); modifiers=[Control], action_dispatch=DocumentMessage::GraphViewOverlayToggle),
entry!(KeyDown(KeyO); modifiers=[Alt], action_dispatch=DocumentMessage::ToggleOverlaysVisibility),
entry!(KeyDown(KeyS); modifiers=[Alt], action_dispatch=DocumentMessage::ToggleSnapping),
entry!(KeyDown(KeyL); modifiers=[Accel], action_dispatch=DocumentMessage::ToggleSelectedLocked),
entry!(KeyDown(KeyG); modifiers=[Alt], action_dispatch=DocumentMessage::ToggleGridVisibility),

// TransformLayerMessage
entry!(KeyDown(KeyG); action_dispatch=TransformLayerMessage::BeginGrab),
entry!(KeyDown(KeyR); action_dispatch=TransformLayerMessage::BeginRotate),
entry!(KeyDown(KeyS); action_dispatch=TransformLayerMessage::BeginScale),

// PortfolioMessage
entry!(KeyDown(KeyO); modifiers=[Accel], action_dispatch=PortfolioMessage::OpenDocument),
entry!(KeyDown(KeyI); modifiers=[Accel], action_dispatch=PortfolioMessage::Import),
entry!(KeyDown(KeyR); modifiers=[Alt], action_dispatch=PortfolioMessage::ToggleRulers),

// DialogMessage
entry!(KeyDown(KeyE); modifiers=[Accel], action_dispatch=DialogMessage::RequestExportDialog),
entry!(KeyDown(KeyN); modifiers=[Accel], action_dispatch=DialogMessage::RequestNewDocumentDialog),
entry!(KeyDown(Comma); modifiers=[Accel], action_dispatch=DialogMessage::RequestPreferencesDialog),
```

Commencez dans input_mapping.rs et reproduisez le cas Ctrl+A décrit dans l’issue. Examinez les mappages KeyDown indiqués et mettez-les à jour de manière cohérente avec KeyDownNoRepeat, puis vérifiez que les raccourcis qui se chevauchent ne déclenchent qu’une seule action et que les raccourcis concernés des outils, transformations, documents, portfolios et boîtes de dialogue fonctionnent toujours.

Rédigé par le modèle d'indexation à partir du texte de l'issue.