Fix a comment typo on sqlite3ExprAlloc().  No code changes.

FossilOrigin-Name: 518d6220a12fb1289f699ef0821e6adfcd286ed0
diff --git a/src/expr.c b/src/expr.c
index 1062733..04cd36e 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -433,7 +433,7 @@
 ** is responsible for making sure the node eventually gets freed.
 **
 ** If dequote is true, then the token (if it exists) is dequoted.
-** If dequote is false, no dequoting is performance.  The deQuote
+** If dequote is false, no dequoting is performed.  The deQuote
 ** parameter is ignored if pToken is NULL or if the token does not
 ** appear to be quoted.  If the quotes were of the form "..." (double-quotes)
 ** then the EP_DblQuoted flag is set on the expression node.