Implement num_traits::Zero, One, and Pow for Modint

[TonalidadeHidrica]

I added num-traits as an optional dependency so that we may use libraries requiring Zero, One, and so on, only when we know the library is available in that environment.

[TonalidadeHidrica]

Do I need to add a feature flag to the CI script as well? I'm not sure what is the best practice to do so.

[qryxip]

Suggested change

	#[inline]
	fn is_one(&self) -> bool {
	self == &Self::one()
	}

This part can be omitted (unlike Zero, somehow).

[TonalidadeHidrica]

Huh, that's quite surprising :) However, I took a look at the doc to realize that it actually recommends to implement this. So shall we just leave this as it is?

[qryxip]

Before adding num-traits, we need to

• git rm .cargo/config (otherwise it fails to generate docs when Publish library to crates.io #119)
• Instead, write package.metadata.docs.rs as follows:

index 4602b94..3a49247 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,10 @@ keywords = ["competitive"]
 categories = ["algorithms", "data-structures"]
 publish = false

+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--html-in-header", "katex-header.html"]
+
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

 [dependencies]

[qryxip]

Do I need to add a feature flag to the CI script as well? I'm not sure what is the best practice to do so.

We need to do, I think.

[TonalidadeHidrica]

@qryxip I tried removing .cargo/config.toml and editing all-features = true. Am I doing correctly?

Also, I am not sure how to add a feature flag to the CI script, could you help me out? Do I need to add a new matrix for "all features", or maybe another way?