typos in geometric descriptions in the docs

[just-walk]

Unless I'm misunderstanding, it appears that "h" and "f" have been interchanged in the geometric description of the pushforward (Line 73 of propagators.md, specifically). If so, then that document could probably use someone knowledgeable to edit it for clarity. Even with some familiarity with differential geometry, the math is confusing. E.g. which functions are defined on what spaces.

[oxinabox]

The algebraic geometer who wrote that section no longer is involved in the project. It will take a bit to find someone knowledgable and interested.

[sethaxen]

Any of the Manifolds.jl devs could also review this text.

[oxinabox]

that would be appreciated, can you do so or ask someone to?