git: rename internal 'git/fetch' plumbing to 'git/get'

This caused some confusion, so to make it clear that
it's plumbing and has nothing to do with 'git fetch',
rename it.

sys/src/cmd/git/clone

@@ -33,7 +33,7 @@ fn clone{
 		echo '[remote "origin"]'
 		echo '	url='$remote
 	}
-	{git/fetch  $debug $branchflag $remote >[2=3] | awk '
+	{git/get  $debug $branchflag $remote >[2=3] | awk '
 		BEGIN{
 			headref=""
 			if(ENVIRON["branch"] != "")

sys/src/cmd/git/compat

@@ -131,7 +131,7 @@ fn cmd_ls-remote{
 	remote=`$nl{git/conf 'remote "'$1'".url'}
 	if(~ $#remote 0)
 		remote=$1
-	git/fetch -l $remote | awk '/^remote/{print $3"\t"$2}'
+	git/get -l $remote | awk '/^remote/{print $3"\t"$2}'
 }
 
 fn cmd_version{

sys/src/cmd/git/mkfile

@@ -3,7 +3,7 @@
 BIN=/$objtype/bin/git
 TARG=\
 	conf\
-	fetch\
+	get\
 	fs\
 	log\
 	query\

sys/src/cmd/git/pull

@@ -10,7 +10,7 @@ fn update{
 	dflag=()
 	if(! ~ $#debug 0)
 		dflag='-d'
-	{git/fetch $dflag -u $upstream $url >[2=3] || die $status} | awk '
+	{git/get $dflag -u $upstream $url >[2=3] || die $status} | awk '
 	/^remote/{
 		if($2=="HEAD")
 			next