Correct typos in RelNotes-1.6.1

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

Documentation/RelNotes-1.6.1.txt

@@ -59,7 +59,7 @@ on.
 
 * "git daemon" learned --max-connections=<count> option.
 
-* "git diff" learned to mimick --suppress-blank-empty from GNU diff via a
+* "git diff" learned to mimic --suppress-blank-empty from GNU diff via a
   configuration option.
 
 * "git diff" learned to put more sensible hunk headers for Python and
@@ -121,7 +121,7 @@ release, unless otherwise noted.
   is a path in it).
 
 * "git diff --stdin" used to take two trees on a line and compared them,
-  but we droppped support for such a use case long time ago.  This has
+  but we dropped support for such a use case long time ago.  This has
   been resurrected.
 
 * "git filter-branch" failed to rewrite a tag name with slashes in it.

Documentation/git-read-tree.txt

@@ -212,7 +212,7 @@ output after two-tree merge.
 
 Case #3 is slightly tricky and needs explanation.  The result from this
 rule logically should be to remove the path if the user staged the removal
-of the path and then swiching to a new branch.  That however will prevent
+of the path and then switching to a new branch.  That however will prevent
 the initial checkout from happening, so the rule is modified to use M (new
 tree) only when the contents of the index is empty.  Otherwise the removal
 of the path is kept as long as $H and $M are the same.