Merge "Hide signup/login/logout links when they would not work"

diff --cc languages/i18n/en.json
Simple merge

diff --cc languages/i18n/qqq.json
index 562e3e5,7b93742..4395034
--- 1/languages/i18n/qqq.json
--- 2/languages/i18n/qqq.json
+++ b/languages/i18n/qqq.json
@@@ -592,10 -592,14 +592,14 @@@
        "yourpasswordagain": "Since 1.22 no longer used in core, but may be used by some extensions. DEPRECATED",
        "createacct-yourpasswordagain": "In create account form, label for field to re-enter password\n\nSee example: [{{canonicalurl:Special:UserLogin|type=signup}} Special:UserLogin?type=signup]\n{{Identical|Confirm password}}",
        "createacct-yourpasswordagain-ph": "Placeholder text in create account form for re-enter password field.\n\nSee example: [{{canonicalurl:Special:UserLogin|type=signup}} Special:UserLogin?type=signup]",
 -      "userlogin-remembermypassword": "Used as checkbox label in [[Special:UserLogin]]. Parameters:\n* $1 - number of days the login session will be active if checked (Unused but used on-wiki)\n",
 +      "userlogin-remembermypassword": "The text for a check box in [[Special:UserLogin]].",
        "userlogin-signwithsecure": "Text of link to HTTPS login form.\n\nSee example: [[Special:UserLogin]]",
-       "cannotloginnow-title": "Error page title shown when logging in is not possible.",
-       "cannotloginnow-text": "Error page text shown when logging in is not possible. Parameters:\n* $1 - Session type in use that makes it not possible to log in, from a message like {{msg-mw|sessionprovider-mediawiki-session-cookiesessionprovider}}.",
+       "cannotlogin-title": "Error page title shown when logging in is not possible. This is a catch-all when a more specific reason is not available.",
+       "cannotlogin-text": "Error page text shown when logging in is not possible. This is a catch-all when a more specific reason is not available.",
+       "cannotloginnow-title": "Error page title shown when logging in is not possible becuse the session provider in use does the user authentication itself.",
+       "cannotloginnow-text": "Error page text shown when logging in is not possible becuse the session provider in use does the user authentication itself. Parameters:\n* $1 - Session type in use that makes it not possible to log in, from a message like {{msg-mw|sessionprovider-mediawiki-session-cookiesessionprovider}}.",
+       "cannotcreateaccount-title": "Error page title shown when manual account creation is not possible. That probably means the wiki supports some other account creation method, e.g. autocreation by the session provider. (When account creation is possible but the current user does not have permission to do it, a more specific error message is displayed.)",
+       "cannotcreateaccount-text": "Error page text shown when manual account creation is not possible. That probably means the wiki supports some other account creation method, e.g. autocreation by the session provider. (When account creation is possible but the current user does not have permission to do it, a more specific error message is displayed.)",
        "yourdomainname": "Used as label for listbox.",
        "password-change-forbidden": "Error message shown when an external authentication source does not allow the password to be changed.",
        "externaldberror": "This message is thrown when a valid attempt to change the wiki password for a user fails because of a database error or an error from an external system.",