git-am: Clean up the asciidoc documentation

Add --keep to synopsis.

The synopsys used a mix of tabs and spaces, unify to use only
spaces.

Shuffle options around in synopsys and description for grouping
them logically.

Add more gitlink references to other commands.

Various grammatical fixes and improvements.

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-am.txt

@@ -9,9 +9,10 @@ git-am - Apply a series of patches from a mailbox
 SYNOPSIS
 --------
 [verse]
-'git-am' [--signoff] [--dotest=<dir>] [--utf8 | --no-utf8] [--binary] [--3way]
-         [--interactive] [--whitespace=<option>] [-C<n>] [-p<n>]
-	 <mbox>...
+'git-am' [--signoff] [--dotest=<dir>] [--keep] [--utf8 | --no-utf8]
+         [--3way] [--interactive] [--binary]
+         [--whitespace=<option>] [-C<n>] [-p<n>]
+         <mbox>...
 'git-am' [--skip | --resolved]
 
 DESCRIPTION
@@ -40,7 +41,7 @@ OPTIONS
 -u, --utf8::
 	Pass `-u` flag to `git-mailinfo` (see gitlink:git-mailinfo[1]).
 	The proposed commit log message taken from the e-mail
-	are re-coded into UTF-8 encoding (configuration variable
+	is re-coded into UTF-8 encoding (configuration variable
 	`i18n.commitencoding` can be used to specify project's
 	preferred encoding if it is not UTF-8).
 +
@@ -51,31 +52,33 @@ default.   You could use `--no-utf8` to override this.
 	Pass `-n` flag to `git-mailinfo` (see
 	gitlink:git-mailinfo[1]).
 
--b, --binary::
-	Pass `--allow-binary-replacement` flag to `git-apply`
-	(see gitlink:git-apply[1]).
-
 -3, --3way::
 	When the patch does not apply cleanly, fall back on
 	3-way merge, if the patch records the identity of blobs
 	it is supposed to apply to, and we have those blobs
-	locally.
+	available locally.
+
+-b, --binary::
+	Pass `--allow-binary-replacement` flag to `git-apply`
+	(see gitlink:git-apply[1]).
+
+--whitespace=<option>::
+	This flag is passed to the `git-apply` (see gitlink:git-apply[1])
+	program that applies
+	the patch.
+
+-C<n>, -p<n>::
+	These flags are passed to the `git-apply` (see gitlink:git-apply[1])
+	program that applies
+	the patch.
+
+-i, --interactive::
+	Run interactively.
 
 --skip::
 	Skip the current patch.  This is only meaningful when
 	restarting an aborted patch.
 
---whitespace=<option>::
-	This flag is passed to the `git-apply` program that applies
-	the patch.
-
--C<n>, -p<n>::
-	These flags are passed to the `git-apply` program that applies
-	the patch.
-
--i, --interactive::
-	Run interactively, just like git-applymbox.
-
 -r, --resolved::
 	After a patch failure (e.g. attempting to apply
 	conflicting patch), the user has applied it by hand and
@@ -126,7 +129,7 @@ to crunch.  Upon seeing the first patch that does not apply, it
 aborts in the middle, just like 'git-applymbox' does.  You can
 recover from this in one of two ways:
 
-. skip the current one by re-running the command with '--skip'
+. skip the current patch by re-running the command with '--skip'
   option.
 
 . hand resolve the conflict in the working directory, and update