[ex][model] Fix typos

exercises/exercise-model/README.md

@@ -81,7 +81,7 @@ const auto imageFileName = getParam<std::string>("ImageFile");
 const auto imageData = NetPBMReader::readPGM(imageFileName);
 ```
 
-### 3.1: Make Test type tag inherit properties from model type tag
+### 3.1: Make test type tag inherit properties from model type tag
 
 :arrow_right: Include the header `model.hh`
 :arrow_right: To use the new model for this test case, make
@@ -137,7 +137,7 @@ You can get the conductance $K$ via the problem interface `conductance`.
 :arrow_right: Compare the `main.cc` with the `main.cc` of the diffusion example. Notice that we
 use a Newton solver as we want to solve nonlinear equations.
 
-As the DuMux assembler uses numeric differentation to approximate the Jacobian matrix, you do not have to implement
+As the DuMux assembler uses numeric differentiation to approximate the Jacobian matrix, you do not have to implement
 the derivatives of your residual by hand and implement them. This greatly simplifies implementing
 nonlinear equations.
 
@@ -155,7 +155,7 @@ __The final result should look like this:__
 <figure>
     <center>
         <img src="../extradoc/exercisemodel_mri_denoise.gif" alt="denoising"/>
-        <figcaption> <b> Fig.1 </b> - Denosing og MRI image using nonlinear diffusion model.</figcaption>
+        <figcaption> <b> Fig.1 </b> - Denosing of MRI image using nonlinear diffusion model.</figcaption>
     </center>
 </figure>
 
@@ -192,7 +192,7 @@ struct VolumeVariables<TypeTag, TTag::NonlinearDiffusionModel>
 };
 ```
 
-you can now use the interface `imageIntensity` in your local residual instead of the generic `priVar` interface.
+You can now use the interface `imageIntensity` in your local residual instead of the generic `priVar` interface.
 
 In order to simplify the implementation of your custom volume variables, you can
 also inherit from `BasicVolumeVariables` and only implement the additional interface.
@@ -202,7 +202,7 @@ To this end, we typically add an `Indices` struct to the `ModelTraits` in which
 and equation indices are named (e.g. `static constexpr int imageIntensityIdx = 0;`).
 The model traits can be passed to the volume variables class via the Traits class.
 
-:arrow_right: Have a look a the solution to the exercise to see how this is usually implemented.
+:arrow_right: Have a look at the solution of the exercise to see how this is usually implemented.
 
 Names indices allow to address the entries of the local residual vector or the primary variables vector.
 You will see names indices in every DuMux model.