devel/ast-grep: import package

Packaged by wiz@ in wip.

ast-grep(sg) is a CLI tool for code structural search, lint, and
rewriting.

ast-grep is a AST-based tool to search code by pattern code. Think it
as your old-friend grep but it matches AST nodes instead of text. You
can write patterns as if you are writing ordinary code. It will match
all code that has the same syntactical structure. You can use $ sign +
upper case letters as wildcard, e.g. $MATCH, to match any single AST
node. Think it as REGEX dot ., except it is not textual.

(pin)