Singularize "the rest pattern"

Like "the wildcard pattern", there is only one "rest pattern".  Let's
singularize this and add the appropriate redirect.

Author: traviscross

book.toml

@@ -35,6 +35,7 @@ use-boolean-and = true
 "/items/traits.html#object-safety" = "traits.html#dyn-compatibility"
 "/lifetime-elision.html#static-lifetime-elision" = "lifetime-elision.html#const-and-static-elision"
 "/macros-by-example.html#path-based-scope" = "macros-by-example.html#the-macro_export-attribute"
+"/patterns.html#rest-patterns" = "patterns.html#rest-pattern"
 "/procedural-macros.html#attribute-macros" = "procedural-macros.html#the-proc_macro_attribute-attribute"
 "/procedural-macros.html#derive-macros" = "procedural-macros.html#the-proc_macro_derive-attribute"
 "/procedural-macros.html#function-like-procedural-macros" = "procedural-macros.html#the-proc_macro-attribute"

src/patterns.md

@@ -421,7 +421,7 @@ r[patterns.wildcard.refutable]
 The wildcard pattern is always irrefutable.
 
 r[patterns.rest]
-## Rest patterns
+## Rest pattern
 
 r[patterns.rest.syntax]
 ```grammar,patterns
@@ -470,7 +470,8 @@ if let [.., penultimate, _] = slice {
 }
 
 # let tuple = (1, 2, 3, 4, 5);
-// Rest patterns may also be used in tuple and tuple struct patterns.
+// The rest pattern may also be used in tuple and tuple
+// struct patterns.
 match tuple {
     (1, .., y, z) => println!("y={} z={}", y, z),
     (.., 5) => println!("tail must be 5"),

src/syntax-index.md

@@ -100,7 +100,7 @@ This appendix provides an index of tokens and common forms with links to where t
 | `<=`   | Le          | [less than or equal to][comparison] |
 | `@`    | At          | [subpattern binding] |
 | `.`    | Dot         | [field access][field], [tuple index] |
-| `..`   | DotDot      | [range expressions][expr.range], [struct expressions], [rest patterns], [range patterns], [struct patterns] |
+| `..`   | DotDot      | [range expressions][expr.range], [struct expressions], [rest pattern], [range patterns], [struct patterns] |
 | `...`  | DotDotDot   | [variadic functions], [range patterns] |
 | `..=`  | DotDotEq    | [inclusive range expressions][expr.range], [range patterns] |
 | `,`    | Comma       | various separators |
@@ -258,7 +258,7 @@ This appendix provides an index of tokens and common forms with links to where t
 | `"foo"`, `'a'`, `123`, `2.4`, …   | [literal patterns] |
 | `ident`                           | [identifier patterns] |
 | `_`                               | [wildcard pattern] |
-| `..`                              | [range patterns], [rest patterns] |
+| `..`                              | [range patterns], [rest pattern] |
 | `..=`                             | [range patterns] |
 | `&pattern`<br>`&mut pattern`      | [reference patterns] |
 | `path {…}`                        | [struct patterns] |
@@ -403,7 +403,7 @@ This appendix provides an index of tokens and common forms with links to where t
 [relaxed trait bounds]: bound.sized
 [repeat array expressions]: expr.array
 [reserved keyword]: lex.keywords.reserved
-[rest patterns]: patterns.rest
+[rest pattern]: patterns.rest
 [return expressions]: expr.return
 [self parameters]: items.fn.params.self-pat
 [single-element tuple expressions]: expr.tuple