add code style to codeblocks in README.md

Author: perNyfelt

NEWS.md

@@ -2,7 +2,7 @@
 ## version 0.2.0.9000-
 * Added single quotes around object model in Description
 * Hide some methods that are internal only from being listed in the documentation using #' #'@keywords internal
-* Change group name to org.renjin.cran for renjin build to have the same R code work in both Renjin and GNU-R
+* Change group name to org.renjin.cran for the Renjin build to have the same R code work in both Renjin and GNU-R
 
 ## version 0.1.2,  2020-05-06
 * Removed all print calls and replaced with warning or message when relevant

README.md

@@ -12,7 +12,7 @@ You can create and xmlr Document programmatically or by parsing text or a file.
 
 # Creating the DOM programmatically
 To create the following xml
-```
+```xml
 <table xmlns='http://www.w3.org/TR/html4/'>
     <tr>
         <td>Apples</td>
@@ -22,7 +22,7 @@ To create the following xml
 
 ```
 You could do something like this:
-```
+```r
  doc <- Document$new()
   root <- Element$new("table")
   root$setAttribute("xmlns", "http://www.w3.org/TR/html4/")
@@ -35,7 +35,7 @@ You could do something like this:
   doc$setRootElement(root)
 ```
 Or you could do like this:
-```
+```r
 doc2 <- parse.xmlstring("
 <table xmlns='http://www.w3.org/TR/html4/'>
     <tr>