Fix order of Token wrt integer and float

With our interpretation of "first match wins" with alternation, this
fixes a problem where INTEGER_LITERAL was incorrectly in front of
FLOAT_LITERAL.

Otherwise, an input of `1.2` would be interpreted as `INTEGER_LITERAL`,
`PUNCTUATION`, `INTEGER_LITERAL` instead of `FLOAT_LITERAL`.

Author: ehuss

src/tokens.md

@@ -14,8 +14,8 @@ Token ->
     | RAW_BYTE_STRING_LITERAL
     | C_STRING_LITERAL
     | RAW_C_STRING_LITERAL
-    | INTEGER_LITERAL
     | FLOAT_LITERAL
+    | INTEGER_LITERAL
     | LIFETIME_TOKEN
     | PUNCTUATION
     | IDENTIFIER_OR_KEYWORD