Clarify purpose of module aliases in ERC

* doc/misc/erc.texi: Mention that aliases should not be defined for
new modules.
* lisp/erc/erc-common.el (define-erc-module): Refactor slightly for
readability.
(erc-with-all-buffers-of-server): Redo doc string.
* lisp/erc/erc-pcomplete.el: Declare `completion' module's feature and
group as being `erc-pcomplete'.
* test/lisp/erc/erc-tests.el (erc--find-group--real): Assert group
lookup works for "normalized" module name `completion' of
`erc-pcomplete-mode'.

1 files changed, 1 insertions, 0 deletions

diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index a71cc806f6a..2318fed28f2 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -3186,6 +3186,7 @@
   (should (eq (erc--find-group 'autojoin) 'erc-autojoin))
   (should (eq (erc--find-group 'pcomplete 'Completion) 'erc-pcomplete))
   (should (eq (erc--find-group 'capab-identify) 'erc-capab))
+  (should (eq (erc--find-group 'completion) 'erc-pcomplete))
   ;; No group specified.
   (should (eq (erc--find-group 'smiley nil) 'erc))
   (should (eq (erc--find-group 'unmorse nil) 'erc)))