Small docs changes (#52)

Author: joaquimg

docs/src/index.md

@@ -39,7 +39,7 @@ run:
 
 ```julia
 using Pkg
-Pkg.add(url = "https://github.com/jump-dev/MathOptAnalyzer.jl")
+Pkg.add("MathOptAnalyzer")
 ```
 
 ## Usage
@@ -134,12 +134,20 @@ MathOptAnalyzer.summarize(issues[1])
 
 If you don't have a JuMP (or MOI) model, you can still use this package reading from a file.
 
+Given a file that could have been generated by JuMP or not, such as:
 ```julia
 model = Model();
 @variable(model, x >= 0);
 @objective(model, Min, 2 * x + 1);
 filename = joinpath(mktempdir(), "model.mps");
 write_to_file(model, filename; generic_names = true)
-new_model = read_from_file(filename; use_nlp_block = false)
+```
+
+We can read it with JuMP:
+```julia
+filename = joinpath(mktempdir(), "model.mps");
+new_model = read_from_file(filename)
 print(new_model)
 ```
+
+And then proceed with the analysis described above.