Point the documentation link in Cargo.toml to docs.rs

The link in the readme already points there, so better to keep it consistent. As a nice side effect, it upgrades the link to https and no longer throws a flash bang at users of a dark theme.

Cargo.toml

@@ -3,7 +3,7 @@ name = "terminal_size"
 version = "0.1.17"
 authors = ["Andrew Chin <achin@eminence32.net>"]
 description = "Gets the size of your Linux or Windows terminal"
-documentation = "http://eminence.github.io/terminal-size/doc/terminal_size/index.html"
+documentation = "https://docs.rs/crate/terminal_size"
 repository = "https://github.com/eminence/terminal-size"
 keywords = ["terminal", "console", "term", "size", "dimensions"]
 license = "MIT OR Apache-2.0"