[do not merge!] Align CQL's grammar with that of FHIRPath to fix operator precedence inconsistencies

[antvaset]

This branch contains proposed changes to CQL's grammar (and therefore spec) to make operator precedence work the same way it does in FHIRPath.

...some background on this issue

The following is a valid FHIRPath expression:

(0 | 1 | 2).take(2) = 0 | 1

which evaluates to true (you can use this https://hl7.github.io/fhirpath.js/ to confirm). But in CQL it currently throws an error because = takes precedence over |, so it's trying to parse ((0 | 1 | 2).take(2) = 0) | 1 and not (0 | 1 | 2).take(2) = (0 | 1). The pipe operator is defined to be equivalent to union, and union is currently explicitly below = in CQL's operator precedence table (https://cql.hl7.org/03-developersguide.html#operator-precedence). In FHIRPath however, the pipe has higher precedence than = (https://build.fhir.org/ig/HL7/FHIRPath/#operator-precedence).

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 63.71%. Comparing base (179c762) to head (7efaada).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1385 +/- ## ============================================ + Coverage 63.69% 63.71% +0.01% Complexity 2666 2666 ============================================ Files 492 492 Lines 27738 27738 Branches 5511 5511 ============================================ + Hits 17669 17672 +3 + Misses 7828 7825 -3 Partials 2241 2241 ```

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