Fix rust_source() examples (#114)

* Fixing examples of 'rust_source' usage

* Updating docs

* Running {styler}

Author: Ilia-Kosenkov

R/source.R

@@ -55,12 +55,6 @@
 #' fn test( a: &str, b: i64) {
 #'     rprintln!("Data sent to Rust: {}, {}", a, b);
 #' }
-#'
-#' extendr_module! {
-#'     mod rextendr;
-#'     fn hello;
-#'     fn test;
-#' }
 #' )"
 #'
 #' rust_source(code = code)
@@ -82,13 +76,11 @@
 #'     html::push_html(&mut output, parser);
 #'     output
 #'   }
-#'
-#'   extendr_module! {
-#'     mod rextendr;
-#'     fn md_to_html;
-#'   }
 #' )"
-#' rust_source(code = code, dependencies = 'pulldown-cmark = "0.8"')
+#' rust_source(
+#'   code = code,
+#'   dependencies = list(`pulldown-cmark` = "0.8")
+#' )
 #'
 #' md_text <- "# The story of the fox
 #' The quick brown fox **jumps over** the lazy dog.
@@ -128,13 +120,11 @@ rust_source <- function(file, code = NULL,
     # R console displays to the user informaion about compilation steps and
     # potenatial compilation errors.
     out <- ""
-
   } else {
 
     # `NULL` or `FALSE` intercepts standard output from `cargo`.
     # No compilation information is displayed to the user.
     out <- NULL
-
   }
 
   # copy rust code into src/lib.rs and determine library name