Block definition

The start_block variable defines the regular expression used to identify the start of a code block:

Regular expression	Description
^::$	Literal block, which for the sake of this repository is always zsh
^.. code:: zsh	zsh code block
^[^. ][^.].*::$	Implied code block via :: suffixed line, skipping lines that are reST directives

start_block='^(::|\.\. code:: zsh|[^\. ][^\.].*::)$'