Remove unused strict field from ParseInModule

[Scott-Guest]

This PR removes the strict field in ParseInModule.

The field is safe to remove because, after eliminating some dead code,

• The only use of strict in ParseInModule is in parseStringTerm
• strict is (almost) always set to true
• The only place where strict is set to false is through a few calls to RuleGrammarGenerator.getCombinedGrammar in KPrint. However, these usages only ever call getParsingModule and getExtensionModule on the constructed ParseInModule object, neither of which invokes parseStringTerm, so the value of strict here is actually irrelevant.

Note that no actual functionality is lost either - the only live usage of strict in parseStringTerm is now fully controlled by the inferSortChecks argument rather than strict && inferSortChecks.

[Baltoli]

Nice one!