consistency improvements for regex and hashes, etc

Accumulated changes/fixes for improving consistency.

• fileName : improve handling of windows-style path separators
• wordRe / keyType : reduce code duplication in favour of using wordRe more consistently
• hashes : rejig hashing overloads and class-local versions to improve future extensibility

changed milestone to %v2106

added code style enhancement labels

looks good - will take a final spin through on Monday

• walked through various points. Some question about returning label vs bool from appendUniq, but probably not important at the moment.

Declared as label (change in list length from operation) - could be interesting for a version taking a list of items to append.

Test loop ran on Friday (when MR was submitted). Nothing beyond than the usual test-loop failures

• lagrangian/reactingParcelFoam/verticalChannelLTS:
• mesh/snappyHexMesh/motorBike_leakDetection:

Thanks - looks good

approved this merge request

added 12 commits

• 0a4e31a1...41d6b935 - 3 commits from branch develop
• ed686f4e - COMP: missing separator
• 6dc6d7ca - ENH: refactor generic patch fields for code reduction
• cdbc3e2d - ENH: List/DynamicList appendUniq() method
• 57c1fcea - ENH: disentangle testing and quoting of regex characters
• 96a1b86f - ENH: consistency improvements for keyType and wordRe
• b060378d - ENH: improve consistency of fileName handling windows/non-windows (#2057 (closed))
• 95cd8ee7 - ENH: improve hashing overloads of string-types and HashTable/HashSet
• 2b7b3700 - ENH: replace keyType with wordRe for matching selectors.
• cf906387 - ENH: improve dynamicCode consistency

Compare with previous version

mentioned in commit f0035734

merged