[Pharo-dev] [ Review needed] Some easy to review PRs

Some easy to review small improvements (which in turn makes them easier to review): 1) use #isSelectorSymbol instead of #findInternedSelector: https://github.com/pharo-project/pharo/pull/11313 2) Improve: Symbol class>>#internSelector: can just record the symbol https://github.com/pharo-project/pharo/pull/11315 3) optimize MorphExtension>>#valueOfProperty: a little https://github.com/pharo-project/pharo/pull/11314 Marcus