Documentation: spell 'git cmd' without dash throughout

The documentation was quite inconsistent when spelling 'git cmd' if it
only refers to the program, not to some specific invocation syntax:
both 'git-cmd' and 'git cmd' spellings exist.

The current trend goes towards dashless forms, and there is precedent
in 647ac70 (git-svn.txt: stop using dash-form of commands.,
2009-07-07) to actively eliminate the dashed variants.

Replace 'git-cmd' with 'git cmd' throughout, except where git-shell,
git-cvsserver, git-upload-pack, git-receive-pack, and
git-upload-archive are concerned, because those really live in the
$PATH.
diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt
index 19b1daf..d4de2e8 100644
--- a/Documentation/git-cvsserver.txt
+++ b/Documentation/git-cvsserver.txt
@@ -22,7 +22,7 @@
 Usage:
 
 [verse]
-'git cvsserver' [options] [pserver|server] [<directory> ...]
+'git-cvsserver' [options] [pserver|server] [<directory> ...]
 
 OPTIONS
 -------
@@ -206,7 +206,7 @@
 The database can not be reliably regenerated in a
 consistent form after the branch it is tracking has changed.
 Example: For merged branches, 'git-cvsserver' only tracks
-one branch of development, and after a 'git-merge' an
+one branch of development, and after a 'git merge' an
 incrementally updated database may track a different branch
 than a database regenerated from scratch, causing inconsistent
 CVS revision numbers. `git-cvsserver` has no way of knowing which