crate name is too small

[Sherlock-Holo]

for example:

when read https://docs.rs/futures/latest/futures/

the crate name size is big, as the crate name, this size is ok to hint people "the crate name is XXX"

however, when enter a module sub page, the crate name become too small

https://docs.rs/futures/latest/futures/future/index.html

it is too small, even make me wonder if my browser is broken to render the website, so I change to firefox, but nothing changed

also we can see the up spacing is shorter than the lower spacing, tha't so strange

and the source up spacing is short, but the lower spacing is too long, even three times the length

[GuillaumeGomez]

cc @rust-lang/rustdoc-frontend

[notriddle]

We should probably increase the margin at the bottom of the search box, but the rest of it is determined by font metrics, and looks fine with different text.

all red lines in the screenshot are exactly the same height

The problem is that, though the word source is always the same and we can manually adjust it, the breadcrumbs list is variable-sized, so making it look right in one case will make it look wrong in others (notice that the word "future" has no g, j, q, p, or y in it).