Support main branch names in git aliases

Author: hmlendea

rc/gitconfig

@@ -42,7 +42,11 @@
 [alias]
     acp = "!f() { git add . && git commit -m \"$*\" && git push; }; f"
     branches = !git branch -vv
-    cleanup = !"git fetch -p && git branch --merged origin/master | grep -vE '^\\*|master' | xargs -r git branch -d"
+    cleanup = "!f() { \
+        BASE=$(git symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/origin/@@'); \
+        git fetch -p && \
+        git branch --merged origin/$BASE | grep -vE \"^\\*|$BASE\" | xargs -r git branch -d; \
+    }; f"
     deltag = !git tag -d $1 &&  git push origin :refs/tags/$1
     jeff = !git diff --ignore-space-at-eol -b -w --ignore-blank-lines
     lg = !git --no-pager log --reverse --pretty='%C(yellow)%h %C(bold blue)%<(15,trunc)%an%Creset %Cgreen%ad%Creset %s%C(auto)%d%Creset' --date=format:'%Y/%m/%d %H:%M' -n32