Make --ignore-multiline-regex example non-greedy

[vries]

I recently started using --ignore-multiline-regex:

$ codespell -h
  ...
  --ignore-multiline-regex IGNORE_MULTILINE_REGEX
                        regular expression that is used to ignore text that may span
                        multi-line regions. The regex is run with re.DOTALL. For
                        example to allow skipping of regions of Python code using
                        begin/end comments one could use: --ignore-multiline-regex '#
                        codespell:ignore-begin *\n.*# codespell:ignore-end *\n'.
                        Defaults to empty/disabled.

I started out with this simple setup in setup.cfg:

# How to ignore blocks of code.                                                          
ignore-multiline-regex = codespell:ignore-begin.*codespell:ignore-end

Soon I found out that the matching is greedy and that therefore in this example:

/* codespell:ignore-begin */
/* Ignore this: usuable.  */
/* codespell:ignore-end */

/* Don't ignore this: usuable.  */

/* codespell:ignore-begin */
/* Ignore that: usuable.  */
/* codespell:ignore-end */

codespell ignores the "Don't ignore this" line.

I fixed this by doing:

ignore-multiline-regex = codespell:ignore-begin.*codespell:ignore-end
ignore-multiline-regex = codespell:ignore-begin.*?codespell:ignore-end

We should do the same in the example shown by codespell -h.