fix links

Author: Vaibhavdixit02

docs/src/highlevels/modeling_languages.md

@@ -50,7 +50,7 @@ doing standard molecular dynamics approximations.
 
 ## DiffEqFinancial.jl: Financial models for use in the DifferentialEquations ecosystem
 
-The goal of [DiffEqFinancial.jl](https://github.com/SciML/DiffEqFinancial.jl/commits/master) is to be a feature-complete set
+The goal of [DiffEqFinancial.jl](https://github.com/SciML/DiffEqFinancial.jl/) is to be a feature-complete set
 of solvers for the types of problems found in libraries like QuantLib, such as the Heston process or the
 Black-Scholes model.
 

docs/src/showcase/gpu_spde.md

@@ -302,7 +302,7 @@ These last two ways enclose the pointer to our cache arrays locally but still pr
 function f(du,u,p,t) to the ODE solver.
 
 Now, since PDEs are large, many times we don't care about getting the whole timeseries. Using
-the [output controls from DifferentialEquations.jl](https://diffeq.sciml.ai/latest/basics/common_solver_opts.html#Output-Control-1), we can make it only output the final timepoint.
+the [output controls from DifferentialEquations.jl](https://docs.sciml.ai/DiffEqDocs/stable/basics/common_solver_opts/), we can make it only output the final timepoint.
 
 ```julia
 prob = ODEProblem(f, u0, (0.0, 100.0))

docs/src/showcase/symbolic_analysis.md

@@ -118,7 +118,7 @@ Did you implement the DAE incorrectly? No. Is the solver broken? No.
 
 It turns out that this is a property of the DAE that we are attempting to solve.
 This kind of DAE is known as an index-3 DAE. For a complete discussion of DAE
-index, see [this article](https://www.scholarpedia.org/article/Differential-algebraic_equations).
+index, see [this article](http://www.scholarpedia.org/article/Differential-algebraic_equations).
 Essentially, the issue here is that we have 4 differential variables (``x``, ``v_x``, ``y``, ``v_y``)
 and one algebraic variable ``T`` (which we can know because there is no `D(T)`
 term in the equations). An index-1 DAE always satisfies that the Jacobian of