Fix formatting in docs for transposing pytrees

[Mikcl]

{func} is currently present in the rendered docs. There should be no space between {func} and following word.

How it is currently rendered:

https://jax.readthedocs.io/en/latest/working-with-pytrees.html#transposing-pytrees-with-jax-tree-map-and-jax-tree-transpose

To transpose a pytree (turn a list of trees into a tree of lists), JAX has two functions: {func} jax.tree.map (more basic) and jax.tree.transpose (more flexible, complex and verbose).

[google-cla]

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