osc.lua: escape text

Escape all messages in osc.lua, because other than the title they
weren't being escaped at all. If for example you did mpv foo.mp4
'{\fs50}bar.mp4' and script-message osc-playlist, it would just render
the second entry as bar.mp4 in big text.

The title was escaped partially, now the escaping is complete because:

- It escapes \. Backslashes at the end of the title are escaped instead
  of being stripped, and \n, \N and \h are now printed verbatim. In
  particular, "\\n" is no longer converted to space and is printed
  verbatim instead which is more correct.
- Newlines ("\n", not the "\\n" escape sequence) are converted to spaces
  instead of rendering them and messing up the text positioning within
  the OSC.
- Spaces at the start are preserved.

Fixes #11209, fixes #11275.

1 files changed, 1 insertions, 1 deletions

diff --git a/DOCS/man/osc.rst b/DOCS/man/osc.rst
index 61591b7023..9ed338a965 100644
--- a/DOCS/man/osc.rst
+++ b/DOCS/man/osc.rst
@@ -307,7 +307,7 @@ Configurable Options
 
     String that supports property expansion that will be displayed as
     OSC title.
-    ASS tags are escaped, and newlines and trailing slashes are stripped.
+    ASS tags are escaped and newlines are converted to spaces.
 
 ``tooltipborder``
     Default: 1