Add i18n.

services/web/app/views/project/editor.pug

@@ -63,8 +63,8 @@ block content
 					resize-on="layout:chat:resize",
 					minimum-restore-size-west="130"
 					custom-toggler-pane="'west'"
-					custom-toggler-msg-when-open="'Click to close the file tree'"
-					custom-toggler-msg-when-closed="'Click to open the file tree'"
+					custom-toggler-msg-when-open="'" + translate("tooltip_hide_filetree") + "'"
+					custom-toggler-msg-when-closed="'" + translate("tooltip_show_filetree") + "'"
 				)
 					.ui-layout-west
 						include ./editor/file-tree

services/web/app/views/project/editor/editor.pug

@@ -9,8 +9,8 @@ div.full-size(
 	minimum-restore-size-east="300"
 	allow-overflow-on="'center'"
 	custom-toggler-pane="'east'"
-	custom-toggler-msg-when-open="'Click to close the PDF'"
-	custom-toggler-msg-when-closed="'Click to open the PDF'"
+	custom-toggler-msg-when-open="'" + translate("tooltip_hide_pdf") + "'"
+	custom-toggler-msg-when-closed="'" + translate("tooltip_show_pdf") + "'"
 )
 	.ui-layout-center(
 		ng-controller="ReviewPanelController",