Require method in remote file name syntax

Require method in remote file name syntax

* lisp/minibuffer.el (completion--nth-completion):
Do not bind `non-essential'.

* lisp/net/tramp-adb.el (tramp-adb-maybe-open-connection):
* lisp/net/tramp-gvfs.el (tramp-gvfs-maybe-open-connection):
* lisp/net/tramp-sh.el (tramp-maybe-open-connection):
* lisp/net/tramp-smb.el (tramp-smb-maybe-open-connection): Do not call
`tramp-check-proper-method-and-host'.

* lisp/net/tramp-sh.el (tramp-ssh-controlmaster-options): Better traces.
(tramp-maybe-open-connection): Do not use argument for
´tramp-completion-mode-p'.

* lisp/net/tramp.el (tramp-default-method-marker): New defconst.
(tramp-prefix-format, tramp-postfix-method-format)
(tramp-prefix-ipv6-format, tramp-postfix-ipv6-format)
(tramp-prefix-port-format, tramp-postfix-host-format)
(tramp-file-name-regexp, tramp-completion-file-name-regexp):
Use `eq' instead of `eqal'.
(tramp-method-regexp, tramp-domain-regexp)
(tramp-remote-file-name-spec-regexp)
(tramp-file-name-regexp-unified)
(tramp-completion-file-name-regexp-unified)
(tramp-completion-file-name-regexp-separate): Adapt regexp.
(tramp-completion-file-name-handler-alist)
(tramp-run-real-handler): Autoload them.
(tramp-find-method): Handle `tramp-default-method-marker'.
(tramp-check-proper-method-and-host)
(tramp-completion-run-real-handler): Remove them.
(tramp-error-with-buffer, tramp-connectable-p): Do not use
argument for ´tramp-completion-mode-p'.
(tramp-find-foreign-file-name-handler): Remove COMPLETION
argument.  Do not apply heuristic for completion.
(tramp-file-name-handler): Do not modify `non-essential'.
(tramp-completion-file-name-handler): Change implementation.
(tramp-autoload-file-name-handler)
(tramp-completion-handle-file-name-all-completions):
Call `tramp-run-real-handler'.
(tramp-completion-mode-p): Do not autoload.  Remove argument.
Do not apply heuristic for completion.
(tramp-completion-dissect-file-name): Simplify implementation.
(tramp-handle-file-name-as-directory): Call `tramp-connectable-p'.

* test/lisp/net/tramp-tests.el (tramp-test01-file-name-syntax)
(tramp-test02-file-name-dissect)
(tramp-test03-file-name-defaults)
(tramp-test06-directory-file-name): Adapt to the new syntax.
(tramp-test11-copy-file, tramp-test12-rename-file)
(tramp--test-check-files): Deactivate temporarily tests with
quoted file names.
(tramp-test16-directory-files, tramp-test17-insert-directory):
Adapt tests.
(tramp-test24-file-name-completion): Do not check for
completion mode.
(tramp-test31-make-auto-save-file-name): Deactivate temporarily
two tests.