core: remove RPM packaging

The weechat.spec was obsolete and openSUSE has its own here:
https://build.opensuse.org/package/view_file/server:irc/weechat/weechat.spec?expand=1

.gitattributes

@@ -3,6 +3,5 @@
 .git*                  export-ignore
 debian-devel           export-ignore
 debian-stable          export-ignore
-weechat.spec           export-ignore
 .mailmap               export-ignore
 tools/build_debian.sh  export-ignore

ChangeLog.adoc

@@ -62,6 +62,7 @@ Tests::
 Build::
 
   * core: remove build with autotools (issue #1860)
+  * core: remove RPM packaging
 
 [[v3.8]]
 == Version 3.8 (2023-01-08)

doc/en/weechat_dev.en.adoc

@@ -1164,8 +1164,7 @@ Where _component_ is one of following:
 | CMakeLists.txt +
   cmake/* +
   tools/* +
-  weechat.cygport.in +
-  weechat.spec
+  weechat.cygport.in
 | Build
 
 | ci

doc/fr/weechat_dev.fr.adoc

@@ -1184,8 +1184,7 @@ Où _composant_ est :
 | CMakeLists.txt +
   cmake/* +
   tools/* +
-  weechat.cygport.in +
-  weechat.spec
+  weechat.cygport.in
 | Construction
 
 | ci

doc/ja/weechat_dev.ja.adoc

@@ -1240,8 +1240,7 @@ _component_ には以下から 1 つ選んで記入してください:
 | CMakeLists.txt +
   cmake/* +
   tools/* +
-  weechat.cygport.in +
-  weechat.spec |
+  weechat.cygport.in |
 // TRANSLATION MISSING
   Build
 

doc/sr/weechat_dev.sr.adoc

@@ -1133,8 +1133,7 @@ server->hook_timer_sasl = weechat_hook_timer (timeout * 1000,
 | CMakeLists.txt +
   cmake/* +
   tools/* +
-  weechat.cygport.in +
-  weechat.spec
+  weechat.cygport.in
 | Изградња
 
 | ci