spec: fix prose about terminating statements

CL 85215 added prose to provide some minimal intuition for the
definition of a "terminating statement". While the original definition
was perfectly fine, the added prose was actually incorrect: If the
terminating statement is a goto, it might jump to a labeled statement
following that goto in the same block (it could be the very next
statement), and thus a terminating statement does not in fact
"prevent execution of all statements that lexically appear after
it in the same block".

Rather than explaining the special case for gotos with targets that
are lexically following the goto in the same block, this CL opts for
a simpler approach.

Thanks to @3bodar (Github) for finding this.

Fixes #48323.

Change-Id: I8031346250341d038938a1ce6a75d3e687d32c37
Reviewed-on: https://go-review.googlesource.com/c/go/+/349172
Trust: Robert Griesemer <[email protected]>
Trust: Emmanuel Odeke <[email protected]>
Reviewed-by: Matthew Dempsky <[email protected]>
Reviewed-by: Emmanuel Odeke <[email protected]>
Reviewed-by: Rob Pike <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: griesemer

doc/go_spec.html

@@ -1,6 +1,6 @@
 <!--{
 	"Title": "The Go Programming Language Specification",
-	"Subtitle": "Version of Aug 23, 2021",
+	"Subtitle": "Version of Sep 14, 2021",
 	"Path": "/ref/spec"
 }-->
 
@@ -4561,9 +4561,8 @@ <h2 id="Statements">Statements</h2>
 <h3 id="Terminating_statements">Terminating statements</h3>
 
 <p>
-A <i>terminating statement</i> prevents execution of all statements that lexically
-appear after it in the same <a href="#Blocks">block</a>. The following statements
-are terminating:
+A <i>terminating statement</i> interrupts the regular flow of control in
+a <a href="#Blocks">block</a>. The following statements are terminating:
 </p>
 
 <ol>