core: Increase default value for paste_max_lines to 100

Now that pasting text doesn't cause it to be sent immediately, but
rather inserted in the input line, the paste confirmation isn't really
necessary anymore for small pastes. If you paste by mistake you can just
press ctrl-_ to undo it.

Large pastes may cause weechat to hang for a while, so keep the paste
confirmation for those.

If you don't use bracketed paste you would still want to keep it at 1,
because it's not detected as a paste otherwise, but as far as I know
basically all terminal emulators support bracketed paste, so I think
it's fine to disable the confirmation by default.

src/core/wee-config.c

@@ -3574,7 +3574,7 @@ config_weechat_init_options ()
            "(-1 = disable this feature); this option is used only if the bar "
            "item \"input_paste\" is used in at least one bar (by default it "
            "is used in \"input\" bar)"),
-        NULL, -1, INT_MAX, "1", NULL, 0,
+        NULL, -1, INT_MAX, "100", NULL, 0,
         NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
     config_look_prefix[GUI_CHAT_PREFIX_ERROR] = config_file_new_option (
         weechat_config_file, weechat_config_section_look,