Update revision log

Author: cmaglie

build/shared/revisions.txt

@@ -1,6 +1,7 @@
 ARDUINO 1.8.4
 
 [ide]
+* IDE Toolbar can now go full width on 4K display.
 * Environment variable LIBRARY_INDEX_URL is now correctly parsed (LIBRARY_INDEX_URL_GZ can also be optinally specified). Thanks @xardael
 * Added per-board generic option in config file boards.txt for disabling control of dtr+rts. Thanks @d-a-v