Rewrite DSL

[neonWhiteout]

Created a DSL for rewrite:

aged_sir_rewritten = @rewrite aged_sir begin

    :redefs
    v_meanInfectiousContactsPerSv_cINC := cc_C * v_prevalencev_INC_post
    v_meanInfectiousContactsPerSv_cINA := cc_A * v_prevalencev_INA_post

    :parameters
    + fcc
    + fca
    + fac
    + faa

    :dynamic_variables

    + v_CCContacts = fcc * v_prevalencev_INC
    + v_CAContacts = fca * v_prevalencev_INA

    + v_ACContacts = fac * v_prevalencev_INC
    + v_AAContacts = faa * v_prevalencev_INA

    + v_prevalencev_INC_post = v_CCContacts + v_CAContacts
    + v_prevalencev_INA_post = v_ACContacts + v_AAContacts

end

Requires further tests to fix edge case bugs, but currently works with all our examples. Creates L, I and R, defines the two homs and applies the rule.

[codecov[bot]]

Codecov Report

Attention: 89 lines in your changes are missing coverage. Please review.

Comparison is base (e2b3ca8) 49.96% compared to head (d5717e2) 57.90%.

Files	Patch %	Lines
src/syntax/Rewrite.jl	82.57%	77 Missing :warning:
src/StockFlow.jl	62.06%	11 Missing :warning:
src/Syntax.jl	96.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #106 +/- ## ========================================== + Coverage 49.96% 57.90% +7.93% ========================================== Files 9 10 +1 Lines 1523 2012 +489 ========================================== + Hits 761 1165 +404 - Misses 762 847 +85 ```

:umbrella: View full report in Codecov by Sentry.
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[neonWhiteout]

Updated rewrite syntax

• Use = instead of := in redefs
• When deleting, use the :removes header, and don't prepend a -
• When adding, use the header for the type you're adding (eg :stocks, :flows) and don't prepend a +
• :swaps is now called :dyvar_swaps

[neonWhiteout]

The above example in the new syntax would be

aged_sir_rewritten = @rewrite aged_sir begin

    :redefs
    v_meanInfectiousContactsPerSv_cINC = cc_C * v_prevalencev_INC_post
    v_meanInfectiousContactsPerSv_cINA = cc_A * v_prevalencev_INA_post

    :parameters
    fcc
    fca
    fac
    faa

    :dynamic_variables

    v_CCContacts = fcc * v_prevalencev_INC
    v_CAContacts = fca * v_prevalencev_INA

    v_ACContacts = fac * v_prevalencev_INC
    v_AAContacts = faa * v_prevalencev_INA

    v_prevalencev_INC_post = v_CCContacts + v_CAContacts
    v_prevalencev_INA_post = v_ACContacts + v_AAContacts

end