runtime(bitbake): fix multiline Python function parameter syntax

Fix syntax highlighting for def-style Python functions, with their
parameters spanning multiple lines. E.g. the following should match as
valid Python code in Bitbake recipes:

    def myFunction(one, two, \
                   three, four):
        pass

For this to work, use the prefix modifier "\_" before the wildcard ".",
to also match newline characters.

closes: #18565

Signed-off-by: Martin Schwan <[email protected]>
Signed-off-by: Christian Brabandt <[email protected]>

Author: mschwan-phytec

runtime/syntax/bitbake.vim

@@ -4,6 +4,8 @@
 "               Ricardo Salveti <[email protected]>
 " Copyright:    Copyright (C) 2004  Chris Larson <[email protected]>
 "               Copyright (C) 2008  Ricardo Salveti <[email protected]>
+" Last Change:  2022 Jul 25
+" 2025 Oct 13 by Vim project: update multiline function syntax #18565
 "
 " This file is licensed under the MIT license, see COPYING.MIT in
 " this source distribution for the terms.
@@ -95,7 +97,7 @@ syn region bbPyFuncRegion       matchgroup=bbDelimiter start="{\s*$" end="^}\s*$
 
 " BitBake 'def'd python functions
 syn keyword bbPyDef             def contained
-syn region bbPyDefRegion        start='^\(def\s\+\)\([0-9A-Za-z_-]\+\)\(\s*(.*)\s*\):\s*$' end='^\(\s\|$\)\@!' contains=@python
+syn region bbPyDefRegion        start='^\(def\s\+\)\([0-9A-Za-z_-]\+\)\(\s*(\_.*)\s*\):\s*$' end='^\(\s\|$\)\@!' contains=@python
 
 " Highlighting Definitions
 hi def link bbUnmatched         Error