rustdoc: change "variadic tuple" notation to look less like real syntax

Author: notriddle

library/core/src/primitive_docs.rs

@@ -918,10 +918,10 @@ mod prim_str {}
 // linked to as `#trait-implementations-1`
 /// # Trait implementations
 ///
-/// In this documentation the shorthand `(T, ...)` is used to represent tuples of varying length.
-/// When that is used, any trait bound expressed on `T` applies to each element of the tuple
-/// independently. Note that this is a convenience notation to avoid repetitive documentation,
-/// not valid Rust syntax.
+/// In this documentation the shorthand `(T₁, T₂, …, Tₙ)` is used to represent tuples of varying
+/// length. When that is used, any trait bound expressed on `T` applies to each element of the
+/// tuple independently. Note that this is a convenience notation to avoid repetitive
+/// documentation, not valid Rust syntax.
 ///
 /// Due to a temporary restriction in Rust’s type system, the following traits are only
 /// implemented on tuples of arity 12 or less. In the future, this may change:

library/std/src/primitive_docs.rs

@@ -918,10 +918,10 @@ mod prim_str {}
 // linked to as `#trait-implementations-1`
 /// # Trait implementations
 ///
-/// In this documentation the shorthand `(T, ...)` is used to represent tuples of varying length.
-/// When that is used, any trait bound expressed on `T` applies to each element of the tuple
-/// independently. Note that this is a convenience notation to avoid repetitive documentation,
-/// not valid Rust syntax.
+/// In this documentation the shorthand `(T₁, T₂, …, Tₙ)` is used to represent tuples of varying
+/// length. When that is used, any trait bound expressed on `T` applies to each element of the
+/// tuple independently. Note that this is a convenience notation to avoid repetitive
+/// documentation, not valid Rust syntax.
 ///
 /// Due to a temporary restriction in Rust’s type system, the following traits are only
 /// implemented on tuples of arity 12 or less. In the future, this may change:

src/librustdoc/html/format.rs

@@ -1079,7 +1079,7 @@ impl clean::Impl {
                 (self.kind.is_tuple_variadic() || self.kind.is_auto()) {
                 // Hardcoded anchor library/core/src/primitive_docs.rs
                 // Link should match `# Trait implementations`
-                primitive_link_fragment(f, PrimitiveType::Tuple, &format!("({name}, ...)"), "#trait-implementations-1", cx)?;
+                primitive_link_fragment(f, PrimitiveType::Tuple, &format!("({name}₁, {name}₂, …, {name}ₙ)"), "#trait-implementations-1", cx)?;
             } else if let Some(ty) = self.kind.as_blanket_ty() {
                 fmt_type(ty, f, use_absolute, cx)?;
             } else {