[LyX/2.3.x] Improve error message a bit more.

[Richard Kimberly Heck]

commit 1101d85a3a8a1e0b8647de02730d3cb95be6f6ee
Author: Richard Kimberly Heck <rikih...@lyx.org>
Date:   Wed Apr 25 18:43:49 2018 -0400

    Improve error message a bit more.
    
    Sorry to Kornel, who had already updated sk.po!
    
    (cherry picked from commit 821e10154739aa23191998b88a4bb7d9e0390628)
---
 src/Buffer.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index ea13fdc..da3db82 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -4358,7 +4358,8 @@ Buffer::ExportStatus Buffer::doExport(string const & 
target, bool put_in_tempdir
                Alert::error(_("File name error"),
                        bformat(_("The directory path to the document\n%1$s\n"
                            "contains spaces, but your TeX installation does "
-                           "not allow them."), from_ascii(filePath())));
+                           "not allow them. You should save the file to a 
directory "
+                                       "whose name does not contain spaces."), 
from_ascii(filePath())));
                return ExportTexPathHasSpaces;
        } else {
                runparams.nice = false;