* src/doc.c (syms_of_doc) <text-quoting-style>: Clarify that info
manual display is unaffected.
doc: /* Style to use for single quotes in help and messages.
Its value should be a symbol. It works by substituting certain single
quotes for grave accent and apostrophe. This is done in help output
-and in functions like `message' and `format-message'. It is not done
-in `format'.
+\(but not for display of Info manuals) and in functions like `message'
+and `format-message'. It is not done in `format'.
`curve' means quote with curved single quotes ‘like this’.
`straight' means quote with straight apostrophes \\='like this\\='.