gitignore: restore explicit lists and fix them

Range matches are not supported with `+`: https://git-scm.com/docs/gitignore

Also sync `.gitignore` file lists with source files and alphasort them.

Follow-up to 5c31c2e670 #16093
Reported-by: Stefan Eissing
Fixes #16112
Fixes #16115
Closes #16116

docs/examples/.gitignore

@@ -2,4 +2,131 @@
 #
 # SPDX-License-Identifier: curl
 
-/[0-9a-z_-]+
+10-at-a-time
+address-scope
+altsvc
+anyauthput
+block_ip
+cacertinmem
+certinfo
+chkspeed
+connect-to
+cookie_interface
+crawler
+debug
+default-scheme
+ephiperfifo
+evhiperfifo
+externalsocket
+fileupload
+ftp-wildcard
+ftpget
+ftpgetinfo
+ftpgetresp
+ftpsget
+ftpupload
+ftpuploadfrommem
+ftpuploadresume
+getinfo
+getinmemory
+getredirect
+getreferrer
+ghiper
+headerapi
+hiperfifo
+href_extractor
+hsts-preload
+htmltidy
+http-options
+http-post
+http2-download
+http2-pushinmemory
+http2-serverpush
+http2-upload
+http3
+http3-present
+httpcustomheader
+httpput
+httpput-postfields
+https
+imap-append
+imap-authzid
+imap-copy
+imap-create
+imap-delete
+imap-examine
+imap-fetch
+imap-list
+imap-lsub
+imap-multi
+imap-noop
+imap-search
+imap-ssl
+imap-store
+imap-tls
+interface
+ipv6
+keepalive
+localport
+maxconnects
+multi-app
+multi-debugcallback
+multi-double
+multi-event
+multi-formadd
+multi-legacy
+multi-post
+multi-single
+multi-uv
+multithread
+netrc
+parseurl
+persistent
+pop3-authzid
+pop3-dele
+pop3-list
+pop3-multi
+pop3-noop
+pop3-retr
+pop3-ssl
+pop3-stat
+pop3-tls
+pop3-top
+pop3-uidl
+post-callback
+postinmemory
+postit2
+postit2-formadd
+progressfunc
+protofeats
+range
+resolve
+rtsp-options
+sendrecv
+sepheaders
+sessioninfo
+sftpget
+sftpuploadresume
+shared-connection-cache
+simple
+simplepost
+simplessl
+smooth-gtk-thread
+smtp-authzid
+smtp-expn
+smtp-mail
+smtp-mime
+smtp-multi
+smtp-ssl
+smtp-tls
+smtp-vrfy
+sslbackend
+synctime
+threaded-ssl
+unixsocket
+url2file
+urlapi
+usercertinmem
+websocket
+websocket-cb
+xmlstream