Mention Bug Fix in release notes

The `git-gui.exe` and `gitk.exe` wrappers intended to
be used in Git CMD [now handle command-line parameters
correctly](git-for-windows/git#1284).

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

ReleaseNotes.md

@@ -49,6 +49,7 @@ This package contains software from a number of other projects including Bash, z
 * The installer [now detects correctly whether symbolic links can be created by regular users](https://github.com/git-for-windows/build-extra/commit/5e438f707027eb99da1b1b381672e6d7dbc063a8).
 * Git Bash [now renders non-ASCII directories nicely](https://github.com/git-for-windows/build-extra/pull/152).
 * A regression that caused the fetch operation with lots of refs to be a lot slower than before [was fixed](https://github.com/git-for-windows/git/issues/1233).
+* The `git-gui.exe` and `gitk.exe` wrappers intended to be used in Git CMD [now handle command-line parameters correctly](https://github.com/git-for-windows/git/issues/1284).
 
 ## Changes since Git for Windows v2.14.0(2) (August 7th 2017)