\sany whitespace character
spoilerthe literal text spoiler (case sensitive) \s+any whitespace character, repeated at least once
.+any character (except for line terminators), repeated at least once
\na line-feed (newline) character (ASCII 10)
Group body(?<body>[\s\S]+?) +?matches at least one character from the set below:
\sany whitespace character
\Sany non-whitespace character
\na line-feed (newline) character (ASCII 10)
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string