Description of problem:
Starting a Fortran file in VIM with "fortran_more_precise" set causes a syntax error in recent versions.

Version-Release number of selected component (if applicable):
vim-enhanced-8.2.109-1.fc30

How reproducible:
Easily

Steps to Reproduce:
1. Open VIM
2. issue "let fortran_more_precise=1"
3. issue "set syn=fortran"

Actual results:
Error detected while processing /usr/share/vim/vim82/syntax/fortran.vim:
line  188:
E869: (NFA) Unknown operator '\@1'
E475: Invalid argument: fortranTarget^Idisplay^I"\(\<do\s\+\)\@<11=\d\+\>"
line  277:
E869: (NFA) Unknown operator '\@1'
E475: Invalid argument: fortranConstructName "\(\<end\s*forall\s\+\)\@<15=\a\w*\
>"

Expected results:
(no error messages)

Additional info:
I think the bug is in the following two lines (other lines commented out above and below give context):
"if exists("fortran_more_precise")
"  " Numbers as targets
"  syn match fortranTarget       display "\(\<if\s*(.\+)\s*\)\@<=\(\d\+\s*,\s*\)\{2}\d\+\>"
  syn match fortranTarget       display "\(\<do\s\+\)\@<11=\d\+\>"
  syn match fortranTarget       display "\(\<go\s*to\s*(\=\)\@<11=\(\d\+\s*,\s*\)*\d\+\>"
"endif

The two lines in question should be, if my guess is correct,
  syn match fortranTarget       display "\(\<do\s\+\)\@11<=\d\+\>"
  syn match fortranTarget       display "\(\<go\s*to\s*(\=\)\@11<=\(\d\+\s*,\s*\)*\d\+\>"