new alias gdcw for git diff --color-words

Signed-off-by: James R. Miller <james.ryland.miller@gmail.com>

plugins/git/git.plugin.zsh

@@ -86,6 +86,7 @@ alias gcs='git commit -S'
 alias gd='git diff'
 alias gdca='git diff --cached'
 alias gdct='git describe --tags `git rev-list --tags --max-count=1`'
+alias gdcw='git diff --color-words'
 alias gdt='git diff-tree --no-commit-id --name-only -r'
 alias gdw='git diff --word-diff'