git-p4: view spec documentation

Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-p4.txt

@@ -230,12 +230,7 @@ git repository:
 
 --use-client-spec::
 	Use a client spec to find the list of interesting files in p4.
-	The client spec is discovered using 'p4 client -o' which checks
-	the 'P4CLIENT' environment variable and returns a mapping of
-	depot files to workspace files.  Note that a depot path is
-	still required, but files found in the path that match in
-	the client spec view will be laid out according to the client
-	spec.
+	See the "CLIENT SPEC" section below.
 
 Clone options
 ~~~~~~~~~~~~~
@@ -304,6 +299,27 @@ p4 revision specifier on the end:
 See 'p4 help revisions' for the full syntax of p4 revision specifiers.
 
 
+CLIENT SPEC
+-----------
+The p4 client specification is maintained with the 'p4 client' command
+and contains among other fields, a View that specifies how the depot
+is mapped into the client repository.  Git-p4 can consult the client
+spec when given the '--use-client-spec' option or useClientSpec
+variable.
+
+The full syntax for a p4 view is documented in 'p4 help views'.  Git-p4
+knows only a subset of the view syntax.  It understands multi-line
+mappings, overlays with '+', exclusions with '-' and double-quotes
+around whitespace.  Of the possible wildcards, git-p4 only handles
+'...', and only when it is at the end of the path.  Git-p4 will complain
+if it encounters an unhandled wildcard.
+
+The name of the client can be given to git-p4 in multiple ways.  The
+variable 'git-p4.client' takes precedence if it exists.  Otherwise,
+normal p4 mechanisms of determining the client are used:  environment
+variable P4CLIENT, a file referenced by P4CONFIG, or the local host name.
+
+
 BRANCH DETECTION
 ----------------
 P4 does not have the same concept of a branch as git.  Instead,
@@ -387,9 +403,7 @@ git-p4.host::
 
 git-p4.client::
 	Client specified as an option to all p4 commands, with
-	'-c <client>'.  This can also be used as a way to find
-	the client spec for the 'useClientSpec' option.
-	The environment variable 'P4CLIENT' can be used instead.
+	'-c <client>', including the client spec.
 
 Clone and sync variables
 ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -417,10 +431,10 @@ git config --add git-p4.branchList main:branchB
 -------------
 
 git-p4.useClientSpec::
-	Specify that the p4 client spec to be used to identify p4 depot
-	paths of interest.  This is equivalent to specifying the option
-	'--use-client-spec'.  The variable 'git-p4.client' can be used
-	to specify the name of the client.
+	Specify that the p4 client spec should be used to identify p4
+	depot paths of interest.  This is equivalent to specifying the
+	option '--use-client-spec'.  See the "CLIENT SPEC" section above.
+	This variable is a boolean, not the name of a p4 client.
 
 Submit variables
 ~~~~~~~~~~~~~~~~