Added Plugin Descriptions

1) Added plugin descriptions (description source: PrismJS Git)
2) Changed "Bash/Shell script" to "Bash (Unix Shell) script" (wikipedia
style)
3) Changed "C like (used internally)" to "C-like" (PrismJS style)
4) Changed plugin base file double-quotation marks to single-quotation
marks (to make it in-line with getDesc)
Updated markup description

Added examples: (X)HTML, XML, MathML, TeX, SOAP, Arom, SVG, etc.