Fix typos in the doc of flax.linen.Module.bind

[nalzok]

What does this PR do?

Fixes several typos in the documentation for flax.linen.Module.bind.

Checklist

• This PR fixes a minor issue (e.g.: typo or small bug) or improves the docs (you can dismiss the other
  checks if that's the case).
• This change is discussed in a Github issue/discussion (please add a link).
• The documentation and docstrings adhere to the
  documentation guidelines.
• This change includes necessary high-coverage tests.
  (No quality testing = no merge!)

[marcvanzee]

Thank you!

[codecov-commenter]

Codecov Report

Merging #2269 (8fb4476) into main (ffb04e7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #2269   +/-   ##
=======================================
  Coverage   75.80%   75.80%           
=======================================
  Files          61       61           
  Lines        5378     5378           
=======================================
  Hits         4077     4077           
  Misses       1301     1301           

Impacted Files	Coverage Δ
flax/linen/module.py	93.77% <ø> (ø)

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