[LinearAlgebra] Remove unreliable doctests

stdlib/LinearAlgebra/src/LinearAlgebra.jl

@@ -385,7 +385,7 @@ control over the factorization of `A`.
     these are already in a factorized form
 
 # Examples
-```jldoctest
+```julia-repl
 julia> A = [1 2.2 4; 3.1 0.2 3; 4 1 2];
 
 julia> X = [1; 2.5; 3];
@@ -426,7 +426,7 @@ control over the factorization of `A`.
     these are already in a factorized form
 
 # Examples
-```jldoctest
+```julia-repl
 julia> A = [1 2.2 4; 3.1 0.2 3; 4 1 2];
 
 julia> X = [1; 2.5; 3];

stdlib/LinearAlgebra/src/hessenberg.jl

@@ -446,7 +446,7 @@ This is useful because multiple shifted solves `(F + μ*I) \\ b`
 Iterating the decomposition produces the factors `F.Q, F.H, F.μ`.
 
 # Examples
-```jldoctest
+```julia-repl
 julia> A = [4. 9. 7.; 4. 4. 1.; 4. 3. 2.]
 3×3 Matrix{Float64}:
  4.0  9.0  7.0