doc: sparse-checkout: use consistent inline list style

Fix this inline list to use a single style, namely numeric, instead of
`(1)` followed by `(b)`.

Signed-off-by: Wonuk Kim <kimww0306@gmail.com>
Acked-by: Kristoffer Haugsbakk <kristofferhaugsbakk@fastmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: onee-only

Documentation/technical/sparse-checkout.adoc

@@ -66,7 +66,7 @@ sparsity patterns: patterns from $GIT_DIR/info/sparse-checkout used to
 	reasons: (1) users in cone mode specify directories rather than
 	patterns (their directories are transformed into patterns, but
 	users may think you are talking about non-cone mode if you use the
-	word "patterns"), and (b) the sparse specification might
+	word "patterns"), and (2) the sparse specification might
 	transiently differ in the working tree or index from the sparsity
 	patterns (see "Sparse specification vs. sparsity patterns").