runtime(yaml): fix indentation script

Problem:  The indentation of Ansible Playbooks gets messed up after
          gg=G (after 9179ddc060)
Solution: Remove one shiftwidth() that seems to be misplaced.

closes: #19180

Signed-off-by: Bjoern Foersterling <bjoern.foersterling@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/indent/testdir/yaml.in

@@ -26,3 +26,14 @@ list:
   - element2:
       foo: bar
 # END_INDENT
+
+# START_INDENT
+- name: test playbook
+  hosts: localhost
+  gather_facts: false
+
+  tasks:
+    - name: hello world
+      ansible.builtin.debug:
+        msg: "hello world"
+# END_INDENT

runtime/indent/testdir/yaml.ok

@@ -26,3 +26,14 @@ list:
   - element2:
       foo: bar
 # END_INDENT
+
+# START_INDENT
+- name: test playbook
+  hosts: localhost
+  gather_facts: false
+
+  tasks:
+    - name: hello world
+      ansible.builtin.debug:
+        msg: "hello world"
+# END_INDENT

runtime/indent/yaml.vim

@@ -6,6 +6,7 @@
 " 2024 Feb 29 by Vim project: disable mulitline indent by default
 " 2024 Aug 14 by Vim project: fix re-indenting when commenting out lines
 " 2026 Jan 08 by Vim project: fix object indentation in array
+" 2026 Jan 15 by Vim project: fix double shiftwidth from previous change
 
 " Only load this indent file when no other was loaded.
 if exists('b:did_indent')
@@ -146,7 +147,7 @@ function GetYAMLIndent(lnum)
             " Previous mapping key is in a list item (- key:)
             " The key effectively starts at indent + 2 (after "- ")
             " Content under it should be indented relative to the key position
-            return indent(prevmapline) + 2 + shiftwidth()
+            return indent(prevmapline) + 2
         else
             return indent(prevmapline)
         endif