Prepend a space to TSV cells that begin with a special character

This ensures applications like Excel treat them as literal strings instead
of interpreting them as formulas.

Author: sunnavy

share/html/Elements/TSVExport

@@ -145,6 +145,8 @@ while (my $row = $Collection->Next) {
             $val =~ s/(?:\n|\r)+/ /g; $val =~ s{\t}{    }g;
             $val = $no_html->scrub($val);
             $val = HTML::Entities::decode_entities($val);
+            # To prevent injection, add a leading space to make sure excel-ish applications treat it like a literal
+            $val =~ s/^(?=-|\+|=|\@|")/ /;
             $val;
         } @$col)."\n");
     }