Validate value tags

[prymitive]

Fixes #839

[github-actions]

Benchmark diff:

goos: linux
goarch: amd64
pkg: github.com/cloudflare/pint/cmd/pint
cpu: AMD EPYC 7763 64-Core Processor                
              │   old.txt   │              new.txt               │
              │   sec/op    │   sec/op     vs base               │
FindEntries-4   102.6m ± 0%   104.1m ± 1%  +1.54% (p=0.001 n=10)
CheckRules-4    86.97m ± 0%   87.22m ± 2%       ~ (p=0.075 n=10)
geomean         94.44m        95.30m       +0.91%

              │   old.txt    │               new.txt               │
              │     B/op     │     B/op      vs base               │
FindEntries-4   61.10Mi ± 0%   61.33Mi ± 0%  +0.39% (p=0.000 n=10)
CheckRules-4    84.89Mi ± 0%   84.91Mi ± 0%  +0.02% (p=0.000 n=10)
geomean         72.02Mi        72.17Mi       +0.21%

              │   old.txt   │              new.txt               │
              │  allocs/op  │  allocs/op   vs base               │
FindEntries-4   536.0k ± 0%   539.2k ± 0%  +0.60% (p=0.000 n=10)
CheckRules-4    883.6k ± 0%   883.9k ± 0%  +0.03% (p=0.000 n=10)
geomean         688.2k        690.4k       +0.32%

[github-actions]

This pull request was validated by pint.

✔️ No problems found

Stats

Stat	Value
Version	v0.53.0-125-g1453b81
Number of rules parsed	4
Number of rules checked	0
Number of problems found	0
Number of offline checks	0
Number of online checks	0
Checks duration	0

Problems

No problems reported

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.79592% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 94.66%. Comparing base (a5a2579) to head (1453b81).

Files	Patch %	Lines
internal/parser/parser.go	89.13%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #890      +/-   ##
==========================================
- Coverage   94.72%   94.66%   -0.07%     
==========================================
  Files          92       92              
  Lines        8649     8727      +78     
==========================================
+ Hits         8193     8261      +68     
- Misses        313      323      +10     
  Partials      143      143              

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