Speed up import rlcompleter by deferring inspect and re

rlcompleter imports inspect and re at module scope, but neither is needed to import the module or to construct a Completer. Each is used in exactly one completion method:

• inspect: only in Completer._callable_postfix
• re: only in Completer.attr_matches

inspect in particular is a heavy import: it transitively pulls in dis, tokenize, and more. Because rlcompleter is imported during interactive startup (to set up tab completion via readline), this import cost is paid on every interactive session and every import rlcompleter, even though the completion methods may never run.

Linked PRs

• gh-156364

Comienza con el módulo rlcompleter y los puntos de entrada Completer._callable_postfix y Completer.attr_matches mencionados en el issue. Verifica el comportamiento de importación antes y después del cambio, y confirma que el comportamiento de completado sigue siendo correcto mientras que importar rlcompleter ya no carga dependencias no utilizadas.