porters-handbook/versions: Fix table rendering

While here, add a new line before the end of the table; it's a common
issue to add the end of the table markup when adding a new version
entry.

PR:		268427 [1]
Reported by:	otis[1] pauamma (IRC)

documentation/content/en/books/porters-handbook/versions/_index.adoc

@@ -394,6 +394,7 @@ Here is a convenient list of `__FreeBSD_version` values as defined in https://cg
 |gitref:8a96874eeeee5195b0b0952b77227bef6a26d1a6[repository="src",length=12]
 |September 22, 2022
 |14.0-CURRENT after qsort_r prototype modified to match POSIX.
+
 |===
 
 ////
@@ -1301,12 +1302,12 @@ Template:
 |gitref:9cbba5950123f3afedcc5f24c43956e7a26f22f4[repository="src",length=12]
 |June 21, 2022
 |13.1-STABLE after various merges to LinuxKPI.
-|===
 
 |1301510
 |gitref:6820a0512fa6616ee1da46cb0075da80478776f0[repository="src",length=12]
 |December 8, 2022
 |13.1-STABLE after LinuxKPI dmi_matches() fixes.
+
 |===
 
 ////
@@ -2109,6 +2110,7 @@ Template:
 |gitref:6a9031c5e2ba5435aa4ea08ee05c351d5bef035d[repository="src",length=12]
 |October 20, 2022
 |12-STABLE after branching releng/12.4.
+
 |===
 
 ////