Typo "nee" -> "need"

Looks like Silverstripe needs the d.
Merge pull request #1295 from ss23/patch-5

Typo "nee" -> "need"
Removed invalid characters

No idea what those characters were meant to be, so I removed them.
Merge pull request #1296 from ss23/patch-6

Removed invalid characters
Adjusted docs to "simple" theme (thanks Nadeeth Lansakara)
Fix minor formatting issues

Extra spaces in front of Action.
Removed the out of place text on GridField (is that meant to be a link or what?)
Missing a period on the end of some entries.
Merge pull request #1298 from ss23/patch-7

Fix minor formatting issues