Removed unstable commented out text

Author: brauliobz

src/identifiers.md

@@ -18,37 +18,4 @@ Or
    * The identifier is more than one character, `_` alone is not an identifier
    * The remaining characters are alphanumeric or `_`
 
-[keywords]: keywords.html
-
 [^non_ascii_idents] Non-ASCII characters in identifiers are currently feature-gated. See [issue #28979](https://github.com/rust-lang/rust/issues/28979).
-
-<!-- When non-ascii identifiers are actually supported:
-
- > **<sup>Lexer:<sup>**  
- > IDENTIFIER :  
- > &nbsp;&nbsp; &nbsp;&nbsp; XID_start XID_continue<sup>\*</sup>  
- > &nbsp;&nbsp; | `_` XID_continue<sup>+</sup>  
-
-An identifier is any nonempty Unicode string of the following form:
-
-Either
-
-   * The first character has property [`XID_start`]
-   * The remaining characters have property [`XID_continue`]
-
-Or
-
-   * The first character is `_`
-   * The identifier is more than one character, `_` alone is not an identifier
-   * The remaining characters have property [`XID_continue`]
-
-that does _not_ occur in the set of [keywords].
-
-> **Note**: [`XID_start`] and [`XID_continue`] as character properties cover the
-> character ranges used to form the more familiar C and Java language-family
-> identifiers.
-   
-[`XID_start`]:  http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AXID_Start%3A%5D&abb=on&g=&i=
-[`XID_continue`]: http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AXID_Continue%3A%5D&abb=on&g=&i=
-
--->