Update URLs

Author: hadley

README.md

@@ -3,7 +3,7 @@
 <!-- badges: start -->
 [![R-CMD-check](https://github.com/r-lib/xml2/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/r-lib/xml2/actions/workflows/R-CMD-check.yaml)
 [![R build status](https://github.com/r-lib/xml2/workflows/R-CMD-check/badge.svg)](https://github.com/r-lib/xml2/actions)
-[![Coverage Status](https://img.shields.io/codecov/c/github/r-lib/xml2/master.svg)](https://codecov.io/github/r-lib/xml2?branch=master)
+[![Coverage Status](https://img.shields.io/codecov/c/github/r-lib/xml2/master.svg)](https://app.codecov.io/github/r-lib/xml2?branch=main)
 <!-- badges: end -->
 
 The xml2 package is a binding to [libxml2](http://xmlsoft.org), making it easy to work with HTML and XML from R. The API is somewhat inspired by [jQuery](https://jquery.com).

vignettes/modification.Rmd

@@ -171,12 +171,12 @@ gc()
 ## Namespaces ##
 
 We want to construct a document with the following namespace layout. (From
-https://stackoverflow.com/questions/32939229/creating-xml-in-r-with-namespaces/32941524#32941524).
+<https://stackoverflow.com/questions/32939229/creating-xml-in-r-with-namespaces/32941524#32941524>).
 ```xml
 <?xml version = "1.0" encoding="UTF-8"?>
-<sld xmlns="http://www.o.net/sld"
-     xmlns:ogc="http://www.o.net/ogc"
-     xmlns:se="http://www.o.net/se"
+<sld xmlns="http://www.opengis.net/sld"
+     xmlns:ogc="http://www.opengis.net/ogc"
+     xmlns:se="http://www.opengis.net/se"
      version="1.1.0" >
 <layer>
 <se:Name>My Layer</se:Name>
@@ -186,10 +186,11 @@ https://stackoverflow.com/questions/32939229/creating-xml-in-r-with-namespaces/3
 
 ```{r}
 d <- xml_new_root("sld",
-    xmlns = "http://www.o.net/sld",
-    "xmlns:ogc" = "http://www.o.net/ogc",
-    "xmlns:se" = "http://www.o.net/se",
-    version = "1.1.0") %>%
+    "xmlns" = "http://www.opengis.net/sld",
+    "xmlns:ogc" = "http://www.opengis.net/ogc",
+    "xmlns:se" = "http://www.opengis.net//se",
+    version = "1.1.0"
+  ) %>%
   xml_add_child("layer") %>%
   xml_add_child("se:Name", "My Layer") %>%
   xml_root()