[librustdoc] Reform lang string token splitting

Only split doctest lang strings on `,`, ` `, and `\t`. Additionally, to
preserve backwards compatibility with pandoc-style langstrings, strip a
surrounding `{}`, and remove leading `.`s from each token.

Prior to this change, doctest lang strings were split on all
non-alphanumeric characters except `-` or `_`, which limited future
extensions to doctest lang string tokens, for example using `=` for
key-value tokens.

This is a breaking change, although it is not expected to be disruptive,
because lang strings using separators other than `,` and ` ` are not
very common

Author: casey

core/src/option.rs

@@ -336,7 +336,7 @@ impl<T> Option<T> {
     /// assert_eq!(x.expect("fruits are healthy"), "value");
     /// ```
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// let x: Option<&str> = None;
     /// x.expect("fruits are healthy"); // panics with `fruits are healthy`
     /// ```
@@ -372,7 +372,7 @@ impl<T> Option<T> {
     /// assert_eq!(x.unwrap(), "air");
     /// ```
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// let x: Option<&str> = None;
     /// assert_eq!(x.unwrap(), "air"); // fails
     /// ```
@@ -1114,7 +1114,7 @@ impl<T: fmt::Debug> Option<T> {
     /// }
     /// ```
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// #![feature(option_expect_none)]
     ///
     /// use std::collections::HashMap;
@@ -1156,7 +1156,7 @@ impl<T: fmt::Debug> Option<T> {
     /// }
     /// ```
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// #![feature(option_unwrap_none)]
     ///
     /// use std::collections::HashMap;

core/src/result.rs

@@ -112,7 +112,7 @@
 //! assert success with [`expect`]. This will panic if the
 //! write fails, providing a marginally useful message indicating why:
 //!
-//! ```{.no_run}
+//! ```no_run
 //! use std::fs::File;
 //! use std::io::prelude::*;
 //!
@@ -122,7 +122,7 @@
 //!
 //! You might also simply assert success:
 //!
-//! ```{.no_run}
+//! ```no_run
 //! # use std::fs::File;
 //! # use std::io::prelude::*;
 //! # let mut file = File::create("valuable_data.txt").unwrap();
@@ -984,7 +984,7 @@ impl<T, E: fmt::Debug> Result<T, E> {
     ///
     /// Basic usage:
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// let x: Result<u32, &str> = Err("emergency failure");
     /// x.expect("Testing expect"); // panics with `Testing expect: emergency failure`
     /// ```
@@ -1024,7 +1024,7 @@ impl<T, E: fmt::Debug> Result<T, E> {
     /// assert_eq!(x.unwrap(), 2);
     /// ```
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// let x: Result<u32, &str> = Err("emergency failure");
     /// x.unwrap(); // panics with `emergency failure`
     /// ```
@@ -1052,7 +1052,7 @@ impl<T: fmt::Debug, E> Result<T, E> {
     ///
     /// Basic usage:
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// let x: Result<u32, &str> = Ok(10);
     /// x.expect_err("Testing expect_err"); // panics with `Testing expect_err: 10`
     /// ```
@@ -1075,7 +1075,7 @@ impl<T: fmt::Debug, E> Result<T, E> {
     ///
     /// # Examples
     ///
-    /// ```{.should_panic}
+    /// ```should_panic
     /// let x: Result<u32, &str> = Ok(2);
     /// x.unwrap_err(); // panics with `2`
     /// ```