Modifications summary:
* Moves AST-related functions from rule/utils.go to astutils/ast_utils.go (+ modifies function calls)
* Renames some of these AST-related functions
* Avoids instantiating a printer config at each call to astutils.GoFmt
* Uses astutils.IsIdent and astutils.IsPkgDotName when possible
* fix: panic with interface type and array
* replaces panic with a return of a default string
* review
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Co-authored-by: chavacava <salvadorcavadini+github@gmail.com>
