Add 'b' binding to jump to bookmark table

[ds2606]

Description of Changes

Closes #1304

Adds the natural 'b' binding to jump directly to the bookmark table. This skips a lot of manual navigation to the bookmarks for users who want to use NERDTree as a way to quickly navigate to certain directories with the file explorer.

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New Version Info

Author's Instructions

• Derive a new MAJOR.MINOR.PATCH version number. Increment the:
  • MAJOR version when you make incompatible API changes
  • MINOR version when you add functionality in a backwards-compatible manner
  • PATCH version when you make backwards-compatible bug fixes
• Update CHANGELOG.md, following the established pattern.

Collaborator's Instructions

• Review CHANGELOG.md, suggesting a different version number if necessary.
• After merging, tag the commit using these (Mac-compatible) bash commands:

  git checkout master
  git pull
  sed -n "$(grep -n -m2 '####' CHANGELOG.md | cut -f1 -d: | sed 'N;s/\n/,/')p" CHANGELOG.md | sed '$d'
  git tag -a $(read -p "Tag Name: " tag;echo $tag) -m"$(git show --quiet --pretty=%s)";git push origin --tags

[rzvxa]

@ds2606 Hello sir, I'm sorry to see your beautiful PR has been waiting for this long.
I'm Currently going back into old PRs to find useful unmerged ones like yours. Is there any chance that you have an interest in continuing to work on this PR?

My only issue with this code is using try/catch instead of checking whether or not the bookmark section is open via this function call:

b:NERDTree.ui.getShowBookmarks()

[rzvxa]

We are not doing a new version for each PR anymore, just remove this change log. For now, I'll use the PR titles to write multi-bulletin change logs.

[rzvxa]

Closed in favor of #1394, added you as the co author.