[PATCH 1 of 3 issue4704] histedit: copyedit docstring wording problem I noticed while here

[Augie Fackler]

# HG changeset patch
# User Augie Fackler <augie at google.com>
# Date 1433531528 14400
#      Fri Jun 05 15:12:08 2015 -0400
# Node ID c05ccbe4e58ddcfbc7d6754159d3dfc7f7b681ea
# Parent  a459d4e026c817bc0702470cd99bc06b40ac956e
histedit: copyedit docstring wording problem I noticed while here

diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -385,7 +385,7 @@ def commitfuncfor(repo, src):
 
     - Add a 'histedit_source' entry in extra.
 
-    Note that fold have its own separated logic because its handling is a bit
+    Note that fold has its own separated logic because its handling is a bit
     different and not easily factored out of the fold method.
     """
     phasemin = src.phase()