runtime(vim): Update base-syntax, fix nested function folding (#14397)

Only match function folding start and end patterns at the start of a
line, excluding heredocs and :append/:change/:insert commands.

Fixes #14393

Signed-off-by: Christian Brabandt <cb@256bit.org>
Signed-off-by: Doug Kearns <dougkearns@gmail.com>

runtime/syntax/testdir/input/vim_ex_def_fold.vim

@@ -108,3 +108,23 @@ def Foo()
   "useless string"
 enddef
 
+
+" fold-region ending
+
+def Foo()
+  # enddef
+enddef
+
+def Foo()
+  echo "enddef"
+enddef
+
+def Foo()
+  let x =<< END
+    endfunction
+  END
+enddef
+
+:def Foo()
+:enddef
+

runtime/syntax/testdir/input/vim_ex_def_nested.vim

@@ -0,0 +1,20 @@
+vim9script
+# Vim9 :def command (nested)
+
+class Test
+    const name: string
+
+    def new()
+	def Name(): string
+	    function GiveName()
+		return "any"
+	    endfunction
+
+	    return GiveName()
+	enddef
+
+	this.name = Name()
+    enddef
+endclass
+
+echo Test.new()

runtime/syntax/testdir/input/vim_ex_def_nested_fold.vim

@@ -0,0 +1,22 @@
+vim9script
+# Vim9 :def command (nested)
+# VIM_TEST_SETUP let g:vimsyn_folding = 'f'
+# VIM_TEST_SETUP setl fdc=2 fdm=syntax
+
+class Test
+    const name: string
+
+    def new()
+	def Name(): string
+	    function GiveName()
+		return "any"
+	    endfunction
+
+	    return GiveName()
+	enddef
+
+	this.name = Name()
+    enddef
+endclass
+
+echo Test.new()

runtime/syntax/testdir/input/vim_ex_function_fold.vim

@@ -181,3 +181,43 @@ delfunction foo.bar
 delfunction! Foo
 delfunction foo.bar
 
+
+" fold-region ending
+
+function Foo()
+  " endfunction
+endfunction
+
+function Foo()
+  echo "endfunction"
+endfunction
+
+function Foo()
+  let x =<< END
+    endfunction
+  END
+
+endfunction
+
+function Foo()
+  append
+    endfunction
+.
+endfunction
+
+function Foo()
+  change
+    endfunction
+.
+
+endfunction
+
+function Foo()
+  insert
+    endfunction
+.
+endfunction
+
+:function Foo()
+:endfunction
+

runtime/syntax/testdir/input/vim_ex_function_nested.vim

@@ -0,0 +1,38 @@
+" Vim :def and :function commands (nested)
+
+def FunA(): string
+    def DoFunA(): string
+	return "."
+    enddef
+
+    return DoFunA()
+enddef
+
+def FunB(): string
+    function DoFunB()
+	return ".."
+    endfunction
+
+    return DoFunB()
+enddef
+
+function FunC()
+    def DoFunC(): string
+	return "..."
+    enddef
+
+    return DoFunC()
+endfunction
+
+function FunD()
+    function DoFunD()
+	return "...."
+    endfunction
+
+    return DoFunD()
+endfunction
+
+echo FunA()
+echo FunB()
+echo FunC()
+echo FunD()

runtime/syntax/testdir/input/vim_ex_function_nested_fold.vim

@@ -0,0 +1,40 @@
+" Vim :def and :function commands (nested)
+" VIM_TEST_SETUP let g:vimsyn_folding = 'f'
+" VIM_TEST_SETUP setl fdc=2 fdm=syntax
+
+def FunA(): string
+    def DoFunA(): string
+	return "."
+    enddef
+
+    return DoFunA()
+enddef
+
+def FunB(): string
+    function DoFunB()
+	return ".."
+    endfunction
+
+    return DoFunB()
+enddef
+
+function FunC()
+    def DoFunC(): string
+	return "..."
+    enddef
+
+    return DoFunC()
+endfunction
+
+function FunD()
+    function DoFunD()
+	return "...."
+    endfunction
+
+    return DoFunD()
+endfunction
+
+echo FunA()
+echo FunB()
+echo FunC()
+echo FunD()