[providers] Deprecation of ptpb.pw as a provider

ptpb.pw has been our default provider since 2017-03-23T21:10:25+01:00,
this was introduced in the commit 993db7e.

But now ptpb.pw has been shut down due to extensive abuse:
ptpb/pb#245
ptpb/pb#240

ptpb.pw, you were the best paste service out there and have served
webpaste.el and many others very well. You will be missed.

So Long, and Thanks for All the Fish.

README.org

@@ -49,11 +49,11 @@ Examples:
   ;; Choosing githup gist only
   (setq webpaste-provider-priority '("gist.github.com"))
 
-  ;; Choosing ptpb.pw as first provider and dpaste.de as second
-  (setq webpaste-provider-priority '("ptpb.pw" "dpaste.de"))
+  ;; Choosing ix.io as first provider and dpaste.de as second
+  (setq webpaste-provider-priority '("ix.io" "dpaste.de"))
 
-  ;; Choosing 1) ptpb.pw, 2) dpaste.de, 3) ix.io
-  (setq webpaste-provider-priority '("ptpb.pw" "dpaste.de" "ix.io"))
+  ;; Choosing 1) ix.io, 2) dpaste.de, 3) dpaste.com
+  (setq webpaste-provider-priority '("ix.io" "dpaste.de" "dpaste.com"))
 
   ;; You can always append this list as much as you like, and which providers
   ;; that exists is documented below in the readme.
@@ -67,7 +67,7 @@ This can be added to the =:config= section of use-package:
            ("C-c C-p C-r" . webpaste-paste-region))
     :config
     (progn
-      (setq webpaste-provider-priority '("ptpb.pw" "dpaste.de"))))
+      (setq webpaste-provider-priority '("ix.io" "dpaste.de"))))
 #+END_SRC
 
 ** Only paste plaintext pastes
@@ -173,8 +173,7 @@ webpaste first and then just read the documentation by running this:
   (describe-function 'webpaste--provider)
 #+end_src
 
-* TODO Providers to implement [6/10]
- - [X] ptpb.pw
+* TODO Providers to implement [5/10]
  - [X] ix.io
  - [X] dpaste.com
  - [X] dpaste.de
@@ -183,4 +182,5 @@ webpaste first and then just read the documentation by running this:
  - [ ] paste.debian.net
  - [ ] bpaste.net
  - [ ] eval.in
+ - [ ] ptpb.pw (RIP due to [[https://github.com/ptpb/pb/issues/245][ptpb/pb#245]] & [[https://github.com/ptpb/pb/issues/240][ptpb/pb#240]])
  - [ ] sprunge.us (removed due to [[https://github.com/rupa/sprunge/issues/45][sprunge#45]] that yields 500s)

tests/integration/test-webpaste-providers.el

@@ -18,15 +18,6 @@
   (spy-on 'webpaste--return-url))
 
 
- (it
-  "ci: can paste with ptpb.pw"
-
-  (funcall (webpaste--get-provider-by-name "ptpb.pw") paste-message :sync t)
-
-  (expect (spy-calls-count 'webpaste--return-url) :to-equal 1)
-  (expect (spy-calls-count 'webpaste--paste-text) :to-equal 0))
-
-
  (it
   "ci: can paste with ix.io"
 

webpaste.el

@@ -87,22 +87,7 @@ This uses `browse-url-generic' to open URLs."
 
 
 (defcustom webpaste-providers-alist
-  '(("ptpb.pw"
-     :uri "https://ptpb.pw/"
-     :post-field "c"
-     :lang-uri-separator "/"
-     :lang-overrides ((emacs-lisp-mode . "elisp")
-                      (nix-mode . "nix")
-                      (conf-toml-mode . "toml")
-                      (bash-mode . "bash")
-                      (sh-mode . "sh")
-                      (csh-mode . "csh")
-                      (tcsh-mode . "tcsh")
-                      (python3-mode . "python3")
-                      (nim-mode . "nim"))
-     :success-lambda webpaste--providers-success-location-header)
-
-    ("ix.io"
+  '(("ix.io"
      :uri "http://ix.io/"
      :post-field "f:1"
      :lang-uri-separator "/"