Bug 1369585 - Remove L10n unknown escape sequence for layout.rowColumnPositions. r=me

devtools/client/locales/en-US/layout.properties

@@ -45,4 +45,4 @@ layout.overlayGrid=Overlay Grid
 
 # LOCALIZATION NOTE (layout.rowColumnPositions): The row and column position of a grid
 # cell shown in the grid cell infobar when hovering over the CSS grid outline.
-layout.rowColumnPositions=Row %S \/ Column %S
+layout.rowColumnPositions=Row %S / Column %S