Add PHOBOSSRC urls to std.experimental

std/experimental/logger/core.d

@@ -1,4 +1,7 @@
-///
+// Written in the D programming language.
+/**
+Source: $(PHOBOSSRC std/experimental/logger/_core.d)
+*/
 module std.experimental.logger.core;
 
 import core.sync.mutex : Mutex;

std/experimental/logger/filelogger.d

@@ -1,4 +1,7 @@
-///
+// Written in the D programming language.
+/**
+Source: $(PHOBOSSRC std/experimental/logger/_filelogger.d)
+*/
 module std.experimental.logger.filelogger;
 
 import std.experimental.logger.core;

std/experimental/logger/multilogger.d

@@ -1,4 +1,7 @@
-///
+// Written in the D programming language.
+/**
+Source: $(PHOBOSSRC std/experimental/logger/_multilogger.d)
+*/
 module std.experimental.logger.multilogger;
 
 import std.experimental.logger.core;

std/experimental/logger/nulllogger.d

@@ -1,4 +1,7 @@
-///
+// Written in the D programming language.
+/**
+Source: $(PHOBOSSRC std/experimental/logger/_nulllogger.d)
+*/
 module std.experimental.logger.nulllogger;
 
 import std.experimental.logger.core;

std/experimental/logger/package.d

@@ -1,3 +1,4 @@
+// Written in the D programming language.
 /**
 Implements logging facilities.
 
@@ -176,6 +177,8 @@ $(D ArrayLogger) contains an array of $(D Logger) and also propagates log
 calls to its stored $(D Logger). The $(D NullLogger) does not do anything. It
 will never log a message and will never throw on a log call with $(D LogLevel)
 $(D error).
+
+Source: $(PHOBOSSRC std/experimental/logger/_package.d)
 */
 module std.experimental.logger;