Documentation: fix typos describing date format

This commit corrects a typographical error found in both
date-formats.txt and git-fast-import.txt documentation, where the term
`email format` was mistakenly used instead of `date format`.

Signed-off-by: Xing Xin <xingxin.xx@bytedance.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/date-formats.txt

@@ -11,7 +11,7 @@ Git internal format::
 	For example CET (which is 1 hour ahead of UTC) is `+0100`.
 
 RFC 2822::
-	The standard email format as described by RFC 2822, for example
+	The standard date format as described by RFC 2822, for example
 	`Thu, 07 Apr 2005 22:13:13 +0200`.
 
 ISO 8601::

Documentation/git-fast-import.txt

@@ -303,7 +303,7 @@ and some sanity checks on the numeric values may also be performed.
 	with e.g. bogus timezone values.
 
 `rfc2822`::
-	This is the standard email format as described by RFC 2822.
+	This is the standard date format as described by RFC 2822.
 +
 An example value is ``Tue Feb 6 11:22:18 2007 -0500''.  The Git
 parser is accurate, but a little on the lenient side.  It is the