Merge #40621 fix(ui2)!: legacy 'ruler' inconsistencies

src/nvim/options.lua

@@ -7072,6 +7072,13 @@ local options = {
         Example: >vim
         	set rulerformat=%15(%c%V\ %p%%%)
         <
+        This looks like an item group, but there are some differences in this
+        particular case.  Most notably, the width is fixed and not a minimum,
+        and the ruler is left-aligned, whereas the alignment of item groups is
+        configurable and right-aligned by default.
+
+        When |ui2| is enabled, the ruler no longer has a fixed width and the
+        item group syntax has no special meaning for 'rulerformat'.
       ]=],
       full_name = 'rulerformat',
       modelineexpr = true,