* lisp/tab-line.el (tab-line-tab-name-format-function): New defcustom.

(tab-line-tab-name-format-default): New function as the default value.
(tab-line-format-template): Funcall tab-line-tab-name-format-function.
This is like recently added tab-bar-tab-name-format-function.
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passed #13564
test-fast-inotify

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passed #13565
test-lisp-inotify

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passed #13566
test-lisp-net-inotify

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