Update label for diode

examples/Figures/Charge_Capacity_Compressibility.pdf

examples/Figures/Charge_Capacity_Lambda2.pdf

examples/Figures/Charge_Capacity_Molarity.pdf

...es/Figures/ComparisonNernstPlanck/Convergence_L2error.pdf

...ComparisonNernstPlanck/fractions_$\delta \varphi = 1$.pdf

...omparisonNernstPlanck/fractions_$\delta \varphi = 10$.pdf

...ComparisonNernstPlanck/potential_$\delta \varphi = 1$.pdf

...omparisonNernstPlanck/potential_$\delta \varphi = 10$.pdf

examples/Figures/ComparisonNernstPlanck/potential_01.pdf

examples/Figures/ComparisonNernstPlanck/potential_10.pdf

.../ComparisonNernstPlanck/pressure_$\delta \varphi = 1$.pdf

...ComparisonNernstPlanck/pressure_$\delta \varphi = 10$.pdf

examples/Figures/Compressibility.pdf

...rolyticDiode/ElectrolyticDiode_BackwardBias_$\varphi$.pdf

.../ElectrolyticDiode/ElectrolyticDiode_BackwardBias_$p$.pdf

...lectrolyticDiode/ElectrolyticDiode_BackwardBias_$y_A$.pdf

...lectrolyticDiode/ElectrolyticDiode_BackwardBias_$y_C$.pdf

...lectrolyticDiode/ElectrolyticDiode_BackwardBias_$y_S$.pdf

...es/Figures/ElectrolyticDiode/ElectrolyticDiode_Domain.pdf

...trolyticDiode/ElectrolyticDiode_ForwardBias_$\varphi$.pdf