Update AsPrimitive Safety docs for rust 1.45

[martin-t]

Fixes #174

The safety section should not be removed entirely since people might be using older compilers (as was pointed out to me in a related issue in the vek crate).

However, this and followup comments indicate that the second case (float to float) was never UB in the first place - should the second example be removed?

[cuviper]

Hi,

However, this and followup comments indicate that the second case (float to float) was never UB in the first place - should the second example be removed?

Yes, I think we can remove that altogether -- would you like to do that here?

[martin-t]

Sure, I also changed the phrasing into past tense in the first example and removed the bullet point since it's no longer a list. Is is ok like this?

[cuviper]

Works for me, thanks!

bors r+

[bors[bot]]

Build succeeded:

• Format
• No Std
• Test (1.15.0)
• Test (1.20.0)
• Test (1.26.0)
• Test (1.31.0)
• Test (1.8.0)
• Test (beta)
• Test (i586)
• Test (nightly)
• Test (stable)