core: Fix regex for constants in the Python stub generator

In Python raw strings, newlines can't be escaped with a backslash. If
you do that, both the backslash and the newline become part of the
string. This meant that the regex for constants both started and ended
with a newline which caused every other constant to be skipped.

src/plugins/python/weechat.pyi

@@ -6,26 +6,44 @@
 from typing import Dict
 
 WEECHAT_RC_OK: int
+WEECHAT_RC_OK_EAT: int
 WEECHAT_RC_ERROR: int
 WEECHAT_CONFIG_READ_OK: int
+WEECHAT_CONFIG_READ_MEMORY_ERROR: int
 WEECHAT_CONFIG_READ_FILE_NOT_FOUND: int
+WEECHAT_CONFIG_WRITE_OK: int
 WEECHAT_CONFIG_WRITE_ERROR: int
+WEECHAT_CONFIG_WRITE_MEMORY_ERROR: int
 WEECHAT_CONFIG_OPTION_SET_OK_CHANGED: int
+WEECHAT_CONFIG_OPTION_SET_OK_SAME_VALUE: int
 WEECHAT_CONFIG_OPTION_SET_ERROR: int
+WEECHAT_CONFIG_OPTION_SET_OPTION_NOT_FOUND: int
 WEECHAT_CONFIG_OPTION_UNSET_OK_NO_RESET: int
+WEECHAT_CONFIG_OPTION_UNSET_OK_RESET: int
 WEECHAT_CONFIG_OPTION_UNSET_OK_REMOVED: int
+WEECHAT_CONFIG_OPTION_UNSET_ERROR: int
 WEECHAT_LIST_POS_SORT: str
+WEECHAT_LIST_POS_BEGINNING: str
 WEECHAT_LIST_POS_END: str
 WEECHAT_HOTLIST_LOW: str
+WEECHAT_HOTLIST_MESSAGE: str
 WEECHAT_HOTLIST_PRIVATE: str
+WEECHAT_HOTLIST_HIGHLIGHT: str
 WEECHAT_HOOK_PROCESS_RUNNING: int
+WEECHAT_HOOK_PROCESS_ERROR: int
 WEECHAT_HOOK_CONNECT_OK: int
+WEECHAT_HOOK_CONNECT_ADDRESS_NOT_FOUND: int
 WEECHAT_HOOK_CONNECT_IP_ADDRESS_NOT_FOUND: int
+WEECHAT_HOOK_CONNECT_CONNECTION_REFUSED: int
 WEECHAT_HOOK_CONNECT_PROXY_ERROR: int
+WEECHAT_HOOK_CONNECT_LOCAL_HOSTNAME_ERROR: int
 WEECHAT_HOOK_CONNECT_GNUTLS_INIT_ERROR: int
+WEECHAT_HOOK_CONNECT_GNUTLS_HANDSHAKE_ERROR: int
 WEECHAT_HOOK_CONNECT_MEMORY_ERROR: int
+WEECHAT_HOOK_CONNECT_TIMEOUT: int
 WEECHAT_HOOK_CONNECT_SOCKET_ERROR: int
 WEECHAT_HOOK_SIGNAL_STRING: str
+WEECHAT_HOOK_SIGNAL_INT: str
 WEECHAT_HOOK_SIGNAL_POINTER: str