Certain linters and formatters support fixing linting and formatting
issues (fix mode). Before this change, Super-linter runs linters and
formatters in a mode that doesn't modify the source code in any way
(check only mode).
With this change, Super-linter supports running linters and formatters
in fix mode if explicitly requested by the configuration. If the
configuration includes a variable named FIX_<language_name>,
Super-linters modifies the command to run the linter or formatter for
<language_name> to enable fix mode.
The modifications to the linter or formatter command that Super-linter
applies depend on what is the default for a particular linter: it either
removes or adds options to the command to run the linter or formatter.
