fix(options): don't update curswant for 'winhl' or 'winbl' (#27515)

test/functional/editor/mode_normal_spec.lua

@@ -0,0 +1,22 @@
+-- Normal mode tests.
+
+local helpers = require('test.functional.helpers')(after_each)
+local clear = helpers.clear
+local feed = helpers.feed
+local fn = helpers.fn
+local command = helpers.command
+local eq = helpers.eq
+
+describe('Normal mode', function()
+  before_each(clear)
+
+  it('setting &winhighlight or &winblend does not change curswant #27470', function()
+    fn.setline(1, { 'long long lone line', 'short line' })
+    feed('ggfi')
+    local pos = fn.getcurpos()
+    feed('j')
+    command('setlocal winblend=10 winhighlight=Visual:Search')
+    feed('k')
+    eq(pos, fn.getcurpos())
+  end)
+end)