docs: Fixed HTML title

[fg-mindee]

With the new documentation theme, the HTML page title (the one appearing on tabs) is now "docTR 0.5.0a0-git documentation" which isn't very user-friendly. This PR sets it as "docTR documentation" (on the former theme, we had "docTR: Document Text Recognition documentation - v0.5.0a0-git")

Any feedback is welcome!

[codecov]

Codecov Report

Merging #864 (7a37c63) into main (4ffdd97) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #864   +/-   ##
=======================================
  Coverage   94.84%   94.84%           
=======================================
  Files         133      133           
  Lines        5200     5200           
=======================================
  Hits         4932     4932           
  Misses        268      268           

Flag	Coverage Δ
unittests	94.84% <ø> (ø)

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Impacted Files	Coverage Δ
doctr/transforms/modules/base.py	94.59% <0.00%> (ø)

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[charlesmindee]

Thanks!