Refactor error messages and function signatures across multiple notebooks for clarity and consistency

- Updated error messages in Gauss method and numerical methods to use variables for better readability.
- Added return type hints to function signatures in various notebooks to improve code documentation.
- Corrected minor grammatical issues in docstrings for better clarity.
- Adjusted print statements and list concatenations for improved output formatting.
- Enhanced plotting functions to ensure consistent figure handling.

M2/Deep Learning/TP3 - Compléments/TP3 - Starter.ipynb

@@ -295,7 +295,7 @@
    ],
    "source": [
     "def get_model() -> keras.Model:\n",
-    "    model = keras.Sequential(\n",
+    "    return keras.Sequential(\n",
     "        [\n",
     "            keras.layers.InputLayer(shape=(32, 32, 3)),\n",
     "            keras.layers.Conv2D(\n",
@@ -330,7 +330,6 @@
     "        ],\n",
     "    )\n",
     "\n",
-    "    return model\n",
     "\n",
     "\n",
     "model = get_model()\n",
@@ -371,14 +370,12 @@
     "        metrics=[\"accuracy\"],\n",
     "    )\n",
     "\n",
-    "    history = model.fit(\n",
+    "    return model.fit(\n",
     "        X_train,\n",
     "        y_train,\n",
     "        validation_data=(X_valid, y_valid),\n",
     "        **kwargs,\n",
-    "    )\n",
-    "\n",
-    "    return history"
+    "    )\n"
    ]
   },
   {