Use real markdown footnote for # sets.

Author: ehuss

src/tokens.md

@@ -24,7 +24,7 @@ Literals are tokens used in [literal expressions].
 
 #### Characters and strings
 
-|                                              | Example         | `#` sets\* | Characters  | Escapes             |
+|                                              | Example         | `#` sets[^nsets] | Characters  | Escapes             |
 |----------------------------------------------|-----------------|------------|-------------|---------------------|
 | [Character](#character-literals)             | `'H'`           | 0          | All Unicode | [Quote](#quote-escapes) & [ASCII](#ascii-escapes) & [Unicode](#unicode-escapes) |
 | [String](#string-literals)                   | `"hello"`       | 0          | All Unicode | [Quote](#quote-escapes) & [ASCII](#ascii-escapes) & [Unicode](#unicode-escapes) |
@@ -35,7 +35,7 @@ Literals are tokens used in [literal expressions].
 | [C string](#c-string-literals)               | `c"hello"`      | 0          | All Unicode | [Quote](#quote-escapes) & [Byte](#byte-escapes) & [Unicode](#unicode-escapes)   |
 | [Raw C string](#raw-c-string-literals)       | `cr#"hello"#`   | <256       | All Unicode | `N/A`                                                                           |
 
-\* The number of `#`s on each side of the same literal must be equivalent.
+[^nsets]: The number of `#`s on each side of the same literal must be equivalent.
 
 #### ASCII escapes