Fix indent after an empty tag with '>' in attributes

A line like <input @input="(e) => update(e)" /> was taken as an empty
tag without '/>', as '>' in '=>' matched its end, so the next line was
indented one level less. Skip '>' in quotes, and don't take '/>' as the
end of an empty tag.

test/cases/shared-empty-tag.vim

@@ -0,0 +1,7 @@
+" Empty tags like <input> with or without '/>', and '>' in attribute
+" expressions
+let g:test_flatten = 1
+
+function! Check()
+  call ExpectIndentEachLine()
+endfunction