Enable automatic trimming of trailing whitespace

This happened automatically in go, but needs a bit more push for rust.

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Author: ankon

.editorconfig

@@ -7,6 +7,7 @@ root = true
 [*]
 end_of_line = lf
 insert_final_newline = true
+trim_trailing_whitespace = true
 
 [*.go]
 end_of_line = lf