Encode length and punctuation in key IDs (#1524)

This is to ensure we don't end up using the same string for two
strings using the same words but different length and punctuation.

_plugins/weblate-source-file.rb

@@ -21,8 +21,11 @@ module Weblate
     def self.get(source_text)
       source_text.nil? or source_text.empty? ? source_text
                                              : source_text.strip[0..150]
-                                                          .gsub(/([^\w\d\s\!]|\n)/, '')
-                                                          .tr(' ', '_') << "_KEY"
+                                                          .gsub(/([^\w\d\s\.\?\!]|\n)/, '')
+                                                          .tr(' ', '_') 
+                                                          .tr('.', 'P')
+                                                          .tr('?', 'Q')
+                                                          .tr('!', 'E') << "_" << source_text.length.to_s << "_KEY"
     end
   end