unmark in ranger does not work

[psamim]

Description

In ranger, when I mark files with TAB or C-SPC, I cannot unmark them using u m.

Reproduction guide

• Start Emacs
• Have ranger layer activated
• Open ranger using SPC a r or deer using SPC a d
• Mark a file using TAB or C-SPC
• Unmark the file using u m

Observed behaviour:
Nothing happens and ^[ m is displayed in mini-buffer.

Expected behaviour:
The marked file should be unmarked.

System Info

• OS: gnu/linux
• Emacs: 24.5.1
• Spacemacs: 0.105.21
• Spacemacs branch: nil (rev. 0283f64)
• Graphic display: t
• Distribution: spacemacs
• Editing style: vim
• Completion: helm
• Layers:

((auto-completion :variables auto-completion-enable-sort-by-usage t auto-completion-enable-snippets-in-popup t auto-completion-enable-help-tooltip t)
 better-defaults emacs-lisp javascript haskell python lua c-c   html shell-scripts ess sql go java react git markdown org restclient selectric erc dockerfile latex evil-commentary spell-checking syntax-checking version-control ranger semicolon org-latex-classes psamim-defaults psamim-org psamim-org-zotero psamim-org-reftex)

[psamim]

The problem was due to outdated documentation, pull request created.
punassuming/ranger.el#126