core: update ChangeLog and release notes (issue #1502)

ChangeLog.adoc

@@ -25,6 +25,7 @@ New features::
   * core: add key kbd:[Alt+K] (upper case) to grab raw key and its command (issue #1238)
   * core: add option `key` in command `/debug` (issue #1238)
   * core: force ctrl keys to lower case when they are added (issue #1875)
+  * core: insert multiple pasted lines in input, instead of sending immediately (issue #1502)
   * core: add command `/reset` to reset options to their default values
   * core: add option `rename` in command `/bar`
   * core: add relative move of read marker with `/buffer set unread [+/-]N` (issue #1895)

ReleaseNotes.adoc

@@ -167,6 +167,21 @@ The default aliases can be converted to lower case with the following commands:
 /alias rename WW ww
 ----
 
+[[v4.0.0_insert_multiple_pasted_lines]]
+=== Insert of multiple pasted lines in input
+
+By default multiple pasted lines are now inserted in input and not sent immediately.
+
+To enable this feature, the default value of option `weechat.look.paste_max_lines`
+has been changed to `100` (it was `1`). +
+If needed, you can reset the option to the new default value after upgrade:
+
+----
+/reset weechat.look.paste_max_lines
+----
+
+The option `weechat.look.paste_auto_add_newline` has been removed.
+
 [[v4.0.0_remove_autotools]]
 === Remove build with autotools