Issue 5218: document footnote-separator-markup (issue 349080043 by address@hidden)

[thomasmorley65]

Some nits:


https://codereview.appspot.com/349080043/diff/1/Documentation/notation/spacing.itely
File Documentation/notation/spacing.itely (right):

https://codereview.appspot.com/349080043/diff/1/Documentation/notation/spacing.itely#newcode1082
Documentation/notation/spacing.itely:1082: bottom of the page.  Default:
a centered horizontal line.
I'd go for:
Default: a centered horizontal line, defined in
@file{ly/paper-defaults-init.ly}

https://codereview.appspot.com/349080043/diff/1/Documentation/notation/spacing.itely#newcode1088
Documentation/notation/spacing.itely:1088: @file{ly/titling-init.ly}.
And add here:
@file{ly/paper-defaults-init.ly}

https://codereview.appspot.com/349080043/