Move the general description of literal expressions from tokens.md to literal-expr.md

Author: mattheww

src/expressions/literal-expr.md

@@ -12,15 +12,20 @@
 >    | [FLOAT_LITERAL]\
 >    | [BOOLEAN_LITERAL]
 
-A _literal expression_ consists of one of the [literal](../tokens.md#literals) forms described earlier.
-It directly describes a number, character, string, or boolean value.
+A _literal expression_ is an expression consisting of a single token, rather than a sequence of tokens, that immediately and directly denotes the value it evaluates to, rather than referring to it by name or some other evaluation rule.
+
+A literal is a form of [constant expression], so is evaluated (primarily) at compile time.
+
+Each of the lexical [literal][literal tokens] forms described earlier can make up a literal expression.
 
 ```rust
 "hello";   // string type
 '5';       // character type
 5;         // integer type
 ```
 
+[constant expression]: ../const_eval.md#constant-expressions
+[literal tokens]: ../tokens.md#literals
 [CHAR_LITERAL]: ../tokens.md#character-literals
 [STRING_LITERAL]: ../tokens.md#string-literals
 [RAW_STRING_LITERAL]: ../tokens.md#raw-string-literals

src/tokens.md

@@ -18,11 +18,7 @@ table production] form, and appear in `monospace` font.
 
 ## Literals
 
-A literal is an expression consisting of a single token, rather than a sequence
-of tokens, that immediately and directly denotes the value it evaluates to,
-rather than referring to it by name or some other evaluation rule. A literal is
-a form of [constant expression](const_eval.md#constant-expressions), so is
-evaluated (primarily) at compile time.
+Literals are tokens used in [literal expressions].
 
 ### Examples
 
@@ -667,6 +663,7 @@ Similarly the `r`, `b`, and `br` prefixes used in raw string literals, byte lite
 [if let]: expressions/if-expr.md#if-let-expressions
 [keywords]: keywords.md
 [lazy-bool]: expressions/operator-expr.md#lazy-boolean-operators
+[literal expressions]: expressions/literal-expr.md
 [loop labels]: expressions/loop-expr.md
 [machine types]: types/numeric.md
 [macros]: macros-by-example.md