remove git log --no-merges option

Unfortunately, `--no-merges` doesn't play well with decorations - some
decoractions that are on merge commits (often dev) do not get displayed. We'll
have to live with some merge commits in `glb`, and add --no-merges when useful.

zsh/omz-custom/git.zsh

@@ -13,7 +13,7 @@ alias gbd='git branch -D'
 ## standard log with train tracks
 alias gl='git log --graph --pretty="format:%C(yellow)%h%Cgreen%d %Cblue[%an] %Creset%s... %C(cyan)%ar"'
 ## concise, branch-only log with train tracks
-alias glb='git log --all --simplify-by-decoration --no-merges --pretty="format:%C(yellow)%h%Cgreen%d %Cblue[%an] %Creset%s... %C(cyan)%ar"'
+alias glb='git log --all --simplify-by-decoration --pretty="format:%C(yellow)%h%Cgreen%d %Cblue[%an] %Creset%s... %C(cyan)%ar"'
 ## search through history for particular text
 alias glS='git log -S'
 alias glp='git log --patch'