Add rule to remove a doubled-up "git clone" in a git clone command. (#1106)

Some git hosts will copy the entire clone command, while others just
copy the url, so typing "git clone ", then pasting a git url that
already has a "git clone " on the front is a somewhat common issue.

README.md

@@ -207,6 +207,7 @@ following rules are enabled by default:
 * `git_branch_exists` – offers `git branch -d foo`, `git branch -D foo` or `git checkout foo` when creating a branch that already exists;
 * `git_branch_list` – catches `git branch list` in place of `git branch` and removes created branch;
 * `git_checkout` – fixes branch name or creates new branch;
+* `git_clone_git_clone` – replaces `git clone git clone ...` with `git clone ...`
 * `git_commit_amend` – offers `git commit --amend` after previous commit;
 * `git_commit_reset` – offers `git reset HEAD~` after previous commit;
 * `git_diff_no_index` – adds `--no-index` to previous `git diff` on untracked files;