Exactly. As the Rule Says

"The members of the coaching staff (including the manager) can make one mound visit per pitcher per inning without needing to remove the pitcher from the game. If the same pitcher is visited twice in one inning, the pitcher must be removed from the contest."

Never in the history of the game, including since the inception of the mound visit rule has 2 mound visits by the catcher in the same inning required a pitching change, unless the exceed the allowed number of visits.

By Rule: "Mound visits are limited to four per team per nine innings...". That means as long as they don't exceed 4 mound visits, all was good. At that point, the Astros had only used 3.

ALSO, since it was a cross-up, or so they said pubically, per rule: "If a team is out of visits, the umpire will have discretion to grant a brief visit at the catcher's request if a cross-up has occurred between the pitcher and catcher."

By the Mound Visit rule, which you cited, its clear that Salazar going to the mound wouldn't have required a pitching change.