div sqrt2 regex: Skip unneeded divisibility test; length-=16

This is done for a Step 1 calculation and the "corresponding" one in Step 2, however, in the latter it is unclear why this can be done.

Author: Davidebyzero

regex for dividing by sqrt2, with molecular lookahead.txt

@@ -11,9 +11,8 @@
 (?=
 \5
 (x(x*)) (?# \7 = floor{N / \4}; \8 = \7-1 )
-(?=\7*$)
-(?=(\2\3)+$) (?# \9 = \4 - 1 )
-\9\8*$
+(?=\7*$) (?# we can skip the test for divisibility by \9 because it's guaranteed that \9 <= \7 )
+(\2\3)\8*$ (?# \9 = \4 - 1 )
 )
 (?=
 .*
@@ -77,8 +76,7 @@
 .*(?=\23$)
 (?=\4*(x?(x*)))\24 (?# \24 = M % \4; \25 = \24-1, or 0 if \24==0 )
 (x(x*)) (?# \26 = floor{M / \4}; \27 = \26-1 )
-(?=\26*$)
-(?=\9+$)
+(?=\26*$) (?# we can skip the test for divisibility by \9, but I'm not sure why; TODO: figure out why this is )
 \9\27*$
 )
 (?=