git-gui: Change more 'include' language to 'add'.

I just found a whole slew of places where we still were using the term
'include' rather than 'add' to refer to the act of updating the index
with modifications from the working directory.  To be consistent with
all Git documentation and command line tools, these should be 'add'.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

git-gui

@@ -1935,9 +1935,9 @@ set max_status_desc 0
 foreach i {
 		{__ i plain    "Unmodified"}
 		{_M i mod      "Modified"}
-		{M_ i fulltick "Included in commit"}
+		{M_ i fulltick "Added to commit"}
 		{MM i parttick "Partially included"}
-		{MD i question "Included (but gone)"}
+		{MD i question "Added (but gone)"}
 
 		{_O o plain    "Untracked"}
 		{A_ o fulltick "Added by commit"}
@@ -2360,11 +2360,11 @@ proc do_include_selection {} {
 
 	if {[array size selected_paths] > 0} {
 		include_helper \
-			{Including selected files} \
+			{Adding selected files} \
 			[array names selected_paths]
 	} elseif {$current_diff ne {}} {
 		include_helper \
-			"Including [short_path $current_diff]" \
+			"Adding [short_path $current_diff]" \
 			[list $current_diff]
 	}
 }
@@ -2384,7 +2384,7 @@ proc do_include_all {} {
 		}
 	}
 	include_helper \
-		{Including all modified files} \
+		{Adding all modified files} \
 		$paths
 }
 
@@ -2615,7 +2615,7 @@ proc do_options {} {
 	pack $w.global -side right -fill both -expand 1 -pady 5 -padx 5
 
 	foreach option {
-		{b partialinclude {Allow Partially Included Files}}
+		{b partialinclude {Allow Partially Added Files}}
 		{b pullsummary {Show Pull Summary}}
 		{b trustmtime  {Trust File Modification Timestamps}}
 		{i diffcontext {Number of Diff Context Lines}}
@@ -2871,7 +2871,7 @@ proc toggle_or_diff {w x y} {
 		}
 		?? {
 			update_index \
-				"Including [short_path $path]" \
+				"Adding [short_path $path]" \
 				[list $path] \
 				[concat $after {set ui_status_value {Ready.}}]
 		}