runtime(vim): update indentation plugin for Vim script

Make the indent script aware of enums and ensure those will be correctly
indented.

fixes: #16289
closes: #16293

Co-authored-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Jim Zhou <csd_189@163.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/indent/testdir/vim.in

@@ -947,6 +947,20 @@ Black
 endenum
 " END_INDENT
 
+" START_INDENT
+enum Digits
+INVALID(v:numbermax),  # The null value.
+ZERO(0 * v:numbermin), ONE(2 - 1),
+TWO(1 + 1), THREE(9 / 3), FOUR(1 * 4),
+FIVE(1 + 2 + 2), SIX(36 / 3 / 2), SEVEN(7), EIGHT(2 * 2 * 2),
+NINE(3 + 3 + 3)
+const value: number
+def new(value: number)
+this.value = value
+enddef
+endenum
+" END_INDENT
+
 " START_INDENT
 call prop_type_add('indent_after_literal_dict', #{ foo: 'bar' })
 call prop_type_delete('indent_after_literal_dict')

runtime/indent/testdir/vim.ok

@@ -940,10 +940,24 @@ endinterface
 " START_INDENT
 enum Color
     White,
-	Red,
-	Green,
-	Blue,
-	Black
+    Red,
+    Green,
+    Blue,
+    Black
+endenum
+" END_INDENT
+
+" START_INDENT
+enum Digits
+    INVALID(v:numbermax),  # The null value.
+    ZERO(0 * v:numbermin), ONE(2 - 1),
+    TWO(1 + 1), THREE(9 / 3), FOUR(1 * 4),
+    FIVE(1 + 2 + 2), SIX(36 / 3 / 2), SEVEN(7), EIGHT(2 * 2 * 2),
+    NINE(3 + 3 + 3)
+    const value: number
+    def new(value: number)
+	this.value = value
+    enddef
 endenum
 " END_INDENT