tiff: fix function name in comment

Change-Id: I33d53b519cd495e5b576ad5a3d142abb215a8b1e
Reviewed-on: https://go-review.googlesource.com/c/image/+/579176
Reviewed-by: qiu laidongfeng2 <2645477756@qq.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: shuang cui <imcusg@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

tiff/reader.go

@@ -40,7 +40,7 @@ var errNoPixels = FormatError("not enough pixel data")
 
 const maxChunkSize = 10 << 20 // 10M
 
-// safeReadtAt is a verbatim copy of internal/saferio.ReadDataAt from the
+// safeReadAt is a verbatim copy of internal/saferio.ReadDataAt from the
 // standard library, which is used to read data from a reader using a length
 // provided by untrusted data, without allocating the entire slice ahead of time
 // if it is large (>maxChunkSize). This allows us to avoid allocating giant