Update method signature and example in CSV.read() docstring (#1183)

Co-authored-by: abhro <5664668+abhro@users.noreply.github.com>

Author: quinnj

src/CSV.jl

@@ -79,13 +79,13 @@ include("rows.jl")
 include("write.jl")
 
 """
-`CSV.read(source, sink::T; kwargs...)` => T
+    CSV.read(source, sink::T; kwargs...) => T
 
 Read and parses a delimited file or files, materializing directly using the `sink` function. Allows avoiding excessive copies
 of columns for certain sinks like `DataFrame`.
 
 # Example
-```
+```julia-repl
 julia> using CSV, DataFrames
 
 julia> path = tempname();