give os.symlink and os.link() better parameter names #5564

Doc/library/os.rst

@@ -924,9 +924,10 @@ Files and Directories
    .. versionadded:: 2.3
 
 
-.. function:: link(src, dst)
+.. function:: link(source, link_name)
 
-   Create a hard link pointing to *src* named *dst*. Availability: Unix.
+   Create a hard link pointing to *source* named *link_name*. Availability:
+   Unix.
 
 
 .. function:: listdir(path)
@@ -1246,9 +1247,10 @@ Files and Directories
       Added access to values as attributes of the returned object.
 
 
-.. function:: symlink(src, dst)
+.. function:: symlink(source, link_name)
 
-   Create a symbolic link pointing to *src* named *dst*. Availability: Unix.
+   Create a symbolic link pointing to *source* named *link_name*. Availability:
+   Unix.
 
 
 .. function:: tempnam([dir[, prefix]])

Doc/library/string.rst

@@ -243,6 +243,7 @@ does an index lookup using :func:`__getitem__`.
 Some simple format string examples::
 
    "First, thou shalt count to {0}" # References first positional argument
+   "Bring me a {}"                  # Implicitly references the first positional argument
    "My quest is {name}"             # References keyword argument 'name'
    "Weight in tons {0.weight}"      # 'weight' attribute of first positional arg
    "Units destroyed: {players[0]}"  # First element of keyword argument 'players'.