SBVR — Add (and explain) styling for 90 days where it appears in formal statement

Add (and explain) styling for "90 days" where it appears in a formal
statement

In the 10 Example Rules (several places throughout the Annexes), "90 days"
appears unstyled in a rule statement.

Actions needed:

1) Add styling to "90 days" [pages: 223, 282, 293 (2 places), 306 (2
places)] where it appears in a formally-styled rule statement (i..e., this
does not apply to its use in Notes, etc.)

2) Add an explanatory section to Annex C, using this as an example,
describing in general how an individual that involves the representation of
some 'quantity' is represented in a formal (fully-styled) SBVR expression.
Make reference to other standards/words, as appropriate.
[ref. earlier discussion thread on SBVR-FTF]

1. Correct rule statement Example 2 to read "... is at most 90 rental days." – i.e., to use the name 'rental days' which is defined in the EU-Rent vocabulary as one of the valid instances of RTU. Style "90 rental days" to apply Name style.
2. Correct this Example's Supporting fact type to cite "rental has rental duration".
3. Add "Supporting fact types" as a way of explanation. Note: There is no generalized treatment for quantities and measurement that has been agreed. There are no changes needed in the Annex for SBVR Structured English, which does not try to address the grammatical patterns used for quantities and measurement.
4. Add a Note to the entry for the rule in the EU-Rent ruleset, explaining that this illustrates one possible way to do this.