Fix typos in docstrings

Author: fhagemann

src/ChargeDensities/CylindricalChargeDensity.jl

@@ -18,7 +18,7 @@ An example definition of a cylindrical charge density looks like this:
 ```yaml 
 charge_density:
   name: cylindrical
-  r:  # impurity profile with linear gradient in r
+  r:  # charge density with linear gradient in r
     init: 1.0e-10     # C/m³
     gradient: 1.0e-11 # C/m⁴
 ```

src/ChargeDensities/LinearChargeDensity.jl

@@ -16,8 +16,8 @@ that can each contain `init` for initial values at 0 and `gradient` for gradient
 An example definition of a linear charge density looks like this:
 ```yaml 
 charge_density:
-  name: cylindrical
-  x:  # impurity profile with linear gradient in x
+  name: linear
+  x:  # charge density with linear gradient in x
     init: 1.0e-10     # C/m³
     gradient: 1.0e-11 # C/m⁴
 ```

src/ImpurityDensities/LinearImpurityDensity.jl

@@ -16,7 +16,7 @@ that can each contain `init` for initial values at 0 and `gradient` for gradient
 An example definition of a linear impurity density looks like this:
 ```yaml 
 impurity_density:
-  name: cylindrical
+  name: linear
   x:  # impurity profile with linear gradient in x
     init: 1.0e10     # 1/m³
     gradient: 1.0e11 # 1/m⁴
@@ -58,4 +58,4 @@ end
 
 (*)(scale::Real, lcdm::LinearImpurityDensity{T}) where {T} = LinearImpurityDensity{T}(T.(scale .* lcdm.offsets), T.(scale .* lcdm.gradients))
 
-(+)(offset::Union{<:Real, <:Quantity{<:Real, Unitful.𝐋^(-3)}}, lcdm::LinearImpurityDensity{T}) where {T} = LinearImpurityDensity{T}(T.(to_internal_units(offset) .+ lcdm.offsets), lcdm.gradients)
+(+)(offset::Union{<:Real, <:Quantity{<:Real, Unitful.𝐋^(-3)}}, lcdm::LinearImpurityDensity{T}) where {T} = LinearImpurityDensity{T}(T.(to_internal_units(offset) .+ lcdm.offsets), lcdm.gradients)