fix(marks): handle switching buffer properly (#25763)

test/functional/editor/mark_spec.lua

@@ -24,7 +24,6 @@ describe('named marks', function()
     os.remove(file2)
   end)
 
-
   it("can be set", function()
     command("edit " .. file1)
     command("mark a")
@@ -147,6 +146,20 @@ describe('named marks', function()
     eq({2, 2}, cursor())
   end)
 
+  it("can move to them using :'", function()
+    command("args " .. file1 .. " " .. file2)
+    feed("j")
+    feed("ma")
+    feed("G")
+    command("'a")
+    eq({2, 0}, cursor())
+    feed("mA")
+    command("next")
+    command("'A")
+    eq(1, meths.get_current_buf().id)
+    eq({2, 0}, cursor())
+  end)
+
   it("errors when it can't find the buffer", function()
     command("args " .. file1 .. " " .. file2)
     feed("mA")