[filecase.pro] Beautify and expand a comment (#70)

filecase.pro

@@ -1,15 +1,16 @@
 # NOTICE:
 #
 # Application name defined in TARGET has a corresponding QML filename.
-# If name defined in TARGET is changed, the following needs to be done
-# to match new name:
+# If the name defined in TARGET is changed, the following must be done
+# to match the new name:
 #   - corresponding QML filename must be changed
 #   - desktop icon filename must be changed
 #   - desktop filename must be changed
 #   - icon definition filename in desktop file must be changed
 #   - translation filenames have to be changed
 
-# The name of your application
+# The name of your application, defaults to the name of the project file, see
+# https://doc.qt.io/qt-5/qmake-common-projects.html#building-an-application
 TARGET = filecase
 
 CONFIG += sailfishapp
@@ -160,6 +161,6 @@ HEADERS += \
     src/boxthumbnailer.h
 
 icons.files = icons
-icons.path = /usr/share/filecase/
+icons.path = /usr/share/$$TARGET
 
 INSTALLS += icons