[slides][materialsystem] Fix typos

slides/materialsystem.md

@@ -38,13 +38,13 @@ More resources can be found [in the code documentation](https://dumux.org/docs/d
 
 ## Components
 
-* Define **Thermodynamic relations** (e.g. molar mass, vapor pressure, density) of a **single chemical species** or a fixed mixture of species
+* Define **thermodynamic relations** (e.g. molar mass, vapor pressure, density) of a **single chemical species** or a fixed mixture of species
 * Provide a convenient way to access these quantities
 
 ## Example implementations
 
 * _H2O_ : pure water properties by IAPWS-97
-* _SimpleH2O_ : A simple water implementation at standard conditions
+* _SimpleH2O_ : a simple water implementation at standard conditions
 * _Brine_ : water with a given salt concentration
 * Many more, see [DuMu^x^ components docs](https://dumux.org/docs/doxygen/master/namespace_dumux_1_1_components.html)
 
@@ -176,7 +176,7 @@ _Specifying a solid system is only necessary if you work with a non-isothermal o
 * Capillary pressure-saturation relation after _Brooks and Corey_
 * Effective diffusivity after _Millington and Quirk_
 
-## Van-Genuchten
+## Van Genuchten
 
 $\begin{equation}
 p_c = \frac{1}{\alpha}\left(S_e^{-1/m} -1\right)^{1/n}