<issue_start><issue_comment>Title: Replace standard filter uses RegEx pattern matching instead of Shopify intended simple string matching
username_0: ### Dotliquid version
Any

### Expected behavior
Match Shopify intend, use an extension / additional filter for regex replace
Intend is somewhat vague on Shopify spec which only says matching a string (although the absence of calling out escapes and pattern suggest they are not supported or expected). But they have an issue discussed in which the intend is made clear:
https://github.com/Shopify/liquid/issues/202

### Actual behavior
Standard filter implementation does a RegEx pattern matching. There is no additional filter to distinguish simple string matching from pattern matching

### Steps to reproduce the Problem (you can add files)

{ "Date": "{{ 'MMM "EEE - SS BNBN KLJLsample\\' | replace: '\\', '\\' | replace: '"', '\"'}}"} will generate
{ "Date": "MMM \"EEE - SS BNBN KLJLsample\\\\"}

{ "Date": "{{ 'MMM "EEE - SS BNBN KLJLsample\\' | replace: '\', '\\' | replace: '"', '\"'}}"} will fail with
{ "Date": "Liquid error: parsing "\" - Illegal \ at end of pattern."}

To match Shopify's behavior the second template should generate the first output.

### Discussion
This will be troublesome to fix as clients of dotLiquid are likely to have started relying on the non-compliant implementation so this will be a breaking change -> need for major version up.<issue_closed>