Indent code block with space

Just like the `tab` key indents a block of code, it would be amazing if the browser recognizes a `space` as a request to indent a block of code by one space when more than one line of code is selected. Right now this behavior will replace the code block with a space.

Start by locating the browser code editor handling for the Tab key and space when multiple lines are selected. Reproduce the current replacement behavior, then verify that pressing space indents the selected code block by one space without replacing it.

Written by the indexing model from the issue text.