sphinx-inline-tabs: Link and scroll fixes

[neflyte]

Summary

This PR resolves two issues with sphinx-inline-tabs:

• Inline tab link anchors were not unique for all tabs in a document.
• When following a URL fragment to a sub-tab, the parent tab is clicked first instead of after the desired tab has been clicked. This allows the browser to scroll to the desired tab.

[mattermost-build]

Hello @neflyte,

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[github-actions]

Newest code from neflyte has been published to preview environment for Git SHA 32317f9

[cwarnermm]

Thanks, @neflyte! Here are some examples of where headings and tab labels aren't clickable/linkable from the right nav pane:

http://mattermost-docs-preview-pulls.s3-website-us-east-1.amazonaws.com/8470/deployment-guide/server/deploy-linux.html#itab--Ubuntu--2_1-id4

http://mattermost-docs-preview-pulls.s3-website-us-east-1.amazonaws.com/8470/deployment-guide/server/deploy-linux.html#itab--RHEL-CentOS-Older-releases--3_2-Older-releases

http://mattermost-docs-preview-pulls.s3-website-us-east-1.amazonaws.com/8470/deployment-guide/server/deploy-kubernetes.html#itab--Oracle--4_1-oke-worker-nodes

http://mattermost-docs-preview-pulls.s3-website-us-east-1.amazonaws.com/8470/end-user-guide/preferences/manage-advanced-options.html#itab--Mobile--0_1-Mobile_7

http://mattermost-docs-preview-pulls.s3-website-us-east-1.amazonaws.com/8470/administration-guide/comply/compliance-export.html#itab--Prior-to-Mattermost-v10.5--0_1-Prior-to-Mattermost-v10.5_1

http://mattermost-docs-preview-pulls.s3-website-us-east-1.amazonaws.com/8470/administration-guide/onboard/connected-workspaces.html#itab--System-Console--0_1-System-Console_4