fix: update batch renaming strings to be super super clear (#159)

See: FossifyOrg/General-Discussion#288

Author: naveensingh

commons/src/main/res/values/strings.xml

@@ -213,11 +213,11 @@
     <string name="filename_invalid_characters_placeholder">Filename \'%s\' contains invalid characters</string>
     <string name="extension_cannot_be_empty">Extension cannot be empty</string>
     <string name="source_file_doesnt_exist">Source file %s doesn\'t exist</string>
-    <string name="prepend_filenames">Prepend filenames</string>
-    <string name="append_filenames">Append filenames</string>
+    <string name="prepend_filenames">Add text before filenames</string>
+    <string name="append_filenames">Add text after filenames</string>
     <string name="simple_renaming">Simple renaming</string>
     <string name="pattern_renaming">Pattern</string>
-    <string name="string_to_add">String to add</string>
+    <string name="string_to_add">Text to add</string>
     <string name="rename_date_time_pattern">%Y - year\n%M - month\n%D - day\n%h - hour\n%m - minute\n%s - second\n%i - number increasing from 1</string>
     <string name="filename_without_txt">Filename (without .txt)</string>
     <string name="filename_without_json">Filename (without .json)</string>