runtime(sh): better function support for bash/zsh in indent script

closes: #16052

Signed-off-by: Lukas Zapletal <lzap+git@redhat.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/indent/sh.vim b/runtime/indent/sh.vim
index aa47c6d..184e829 100644
--- a/runtime/indent/sh.vim
+++ b/runtime/indent/sh.vim
@@ -7,6 +7,8 @@
 " License:             Vim (see :h license)
 " Repository:          https://github.com/chrisbra/vim-sh-indent
 " Changelog:
+"          20241411  - Detect dash character in function keyword for
+"                      bash mode (issue #16049)
 "          20190726  - Correctly skip if keywords in syntax comments
 "                      (issue #17)
 "          20190603  - Do not indent in zsh filetypes with an `if` in comments
@@ -195,7 +197,9 @@
 function! s:is_function_definition(line)
   return a:line =~ '^\s*\<\k\+\>\s*()\s*{' ||
        \ a:line =~ '^\s*{' ||
-       \ a:line =~ '^\s*function\s*\k\+\s*\%(()\)\?\s*{'
+       \ a:line =~ '^\s*function\s*\k\+\s*\%(()\)\?\s*{' ||
+       \ ((&ft is# 'zsh' || s:is_bash()) &&
+       \  a:line =~ '^\s*function\s*\S\+\s*\%(()\)\?\s*{' )
 endfunction
 
 function! s:is_array(line)