xo: add page (#2552)

pages/common/xo.md

@@ -0,0 +1,23 @@
+# xo
+
+> A pluggable zero configuration linting utility for JavaScript.
+
+- Lint files in "src":
+
+`xo`
+
+- Lint on a gives set of files:
+
+`xo {{filename}}.js {{filename1}}.js`
+
+- Fix lint issues:
+
+`xo --fix`
+
+- Lint with spaces as indentation instead of tabs:
+
+`xo --space`
+
+- Lint with prettier code style:
+
+`xo --prettier`