[thread.jthread.class] fix typos (#3183)

Author: cpplearner

source/threads.tex

@@ -1390,7 +1390,7 @@
     [[nodiscard]] id get_id() const noexcept;
     [[nodiscard]] native_handle_type native_handle();   // see~\ref{thread.req.native}
 
-    // \ref{thread.jthread.mem}, stop token handling
+    // \ref{thread.jthread.stop}, stop token handling
     [[nodiscard]] stop_source get_stop_source() noexcept;
     [[nodiscard]] stop_token get_stop_token() const noexcept;
     bool request_stop() noexcept;
@@ -1663,7 +1663,7 @@
 
 \indexlibrarymember{get_stop_source}{jthread}%
 \begin{itemdecl}
-[[nodiscard]] stop_source get_stop_source() noexcept
+[[nodiscard]] stop_source get_stop_source() noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -1673,7 +1673,7 @@
 
 \indexlibrarymember{get_stop_token}{jthread}%
 \begin{itemdecl}
-[[nodiscard]] stop_token get_stop_token() const noexcept
+[[nodiscard]] stop_token get_stop_token() const noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}