DOC-2270: add entry to `TinyMCE 7.0 release notes` for mention of removal of `force_hex_color`. (#3158)

* DOC-2270: add entry to TinyMCE 7.0 release notes for removal of force hex color.

* Update modules/ROOT/pages/7.0-release-notes.adoc

Co-authored-by: ltrouton <46954949+ltrouton@users.noreply.github.com>

---------

Co-authored-by: ltrouton <46954949+ltrouton@users.noreply.github.com>

modules/ROOT/pages/7.0-release-notes.adoc

@@ -513,6 +513,15 @@ When adjusting row height through the row dialog, any height styles previously a
 [[removed]]
 == Removed
 
+=== Removed `force_hex_color` option, with the default now being all colors are forced to HEX format and as lower case.
+// #TINY-10436
+
+Previously in {productname} 6, all colors in the content HTML were set to use `rgb` values by default. As the common practice is using `hex` values this change has been **reverted**.
+
+As a result, in {productname} 7, all colors are converted to use `hex` values and the `forced_hex_color` option is removed. The exception being `rgba` color values, they are left as is.
+
+For more information, see xref:migration-from-6x.adoc#force-hex-color[Migrating from {productname} 6 to {productname} 7: "force_hex_color"].
+
 === Removed InsertOrderedList and InsertUnorderedList commands from core.
 // #TINY-10644