Fixed incorrect markdown for code blocks.
Fixed incorrect markdown for code blocks.

Code blocks under "Files & Dependencies", "Basic Usage: jQuery Plugin", and "Basic Usage: Vanilla JS" were displaying incorrectly due to incorrect markdown. Code blocks should be surrounded by backticks or indented with four spaces but not both.
ctrl-freaks/freezeframe.js,ctrl-freaks/freezeframe.js,ctrl-freaks/freezeframe.js,ctrl-freaks/freezeframe.js