regexp/syntax: rename ErrInvalidDepth to ErrNestingDepth
The proposal accepted the name ErrNestingDepth.
For #51684
Change-Id: I702365f19e5e1889dbcc3c971eecff68e0b08727
Reviewed-on: https://go-review.googlesource.com/c/go/+/401854
Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>