ngx.re.gsub options

gistfile1.txt

https://github.com/openresty/lua-nginx-module?tab=readme-ov-file#ngxrematch

```
Specify options to control how the match operation will be performed. The following option characters are supported:

a             anchored mode (only match from the beginning)

d             enable the DFA mode (or the longest token match semantics).
              this requires PCRE 6.0+ or else a Lua exception will be thrown.
              first introduced in ngx_lua v0.3.1rc30.

D             enable duplicate named pattern support. This allows named
              subpattern names to be repeated, returning the captures in
              an array-like Lua table. for example,
                local m = ngx.re.match("hello, world",
                                       "(?<named>\w+), (?<named>\w+)",
                                       "D")
                -- m["named"] == {"hello", "world"}
              this option was first introduced in the v0.7.14 release.
              this option requires at least PCRE 8.12.

i             case insensitive mode (similar to Perl's /i modifier)

j             enable PCRE JIT compilation, this requires PCRE 8.21+ which
              must be built with the --enable-jit option. for optimum performance,
              this option should always be used together with the 'o' option.
              first introduced in ngx_lua v0.3.1rc30.

J             enable the PCRE Javascript compatible mode. this option was
              first introduced in the v0.7.14 release. this option requires
              at least PCRE 8.12.

m             multi-line mode (similar to Perl's /m modifier)

o             compile-once mode (similar to Perl's /o modifier),
              to enable the worker-process-level compiled-regex cache

s             single-line mode (similar to Perl's /s modifier)

u             UTF-8 mode. this requires PCRE to be built with
              the --enable-utf8 option or else a Lua exception will be thrown.

U             similar to "u" but disables PCRE's UTF-8 validity check on
              the subject string. first introduced in ngx_lua v0.8.1.

x             extended mode (similar to Perl's /x modifier)

```