feat: add Squirrel

queries/squirrel/folds.scm

@@ -0,0 +1,27 @@
+[
+  (class_declaration)
+  (function_declaration)
+  (member_declaration)
+  (enum_declaration)
+
+  (array)
+  (block)
+  (table)
+  (anonymous_function)
+  (parenthesized_expression)
+
+  (string)
+  (verbatim_string)
+
+  (comment)
+
+  (if_statement)
+  (else_statement)
+  (while_statement)
+  (do_while_statement)
+  (switch_statement)
+  (for_statement)
+  (foreach_statement)
+  (try_statement)
+  (catch_statement)
+] @fold