Auto merge of #86586 - Smittyvb:https-everywhere, r=petrochenkov

Use HTTPS links where possible

While looking at #86583, I wondered how many other (insecure) HTTP links were in `rustc`. This changes most other `http` links to `https`. While most of the links are in comments or documentation, there are a few other HTTP links that are used by CI that are changed to HTTPS.

Notes:
- I didn't change any to or in licences
- Some links don't support HTTPS :(
- Some `http` links were dead, in those cases I upgraded them to their new places (all of which used HTTPS)

compiler/rustc_parse/src/lexer/unicode_chars.rs

@@ -1,5 +1,5 @@
 // Characters and their corresponding confusables were collected from
-// http://www.unicode.org/Public/security/10.0.0/confusables.txt
+// https://www.unicode.org/Public/security/10.0.0/confusables.txt
 
 use super::StringReader;
 use crate::token;