help: show content for explicitly disabled extension (issue5228)

obsolete: fix minor module documentation issues

debugextensions: hide "ships-with-hg-core" magic string (BC) Since we have "bundled" flag, we no longer need to rephrase "ships-with-hg-core" to show as "internal".

debugextensions: show ships-with-hg-core state as a separate field This is less magical than rephrasing ships-with-hg-core as internal, and we can distinguish "internal" liar. "tested with: internal" will be hidden by the next patch.

test-debugextensions: add dummy extension to make ifcontains() test more solid If testedwith were a string, ifcontains("3.2", testedwith) would match "3.2.1". New test added to cover that.

py3: remove use of *L syntax The int in Python 3 behaves as long so no need of L's in py3. Moreover we dont need long here.

util: rename checkcase() to fscasesensitive() (API) I always read the name "checkcase(path)" as "do we need to check for case folding at this path", but it's actually (I think) meant to be read "check if the file system cares about case at this path". I'm clearly not the only one confused by this as the dirstate has this property: def _checkcase(self): return not util.checkcase(self._join('.hg')) Maybe we should even inverse the function and call it fscasefolding() since that's what all callers care about?

manifest: call m1.load and m2.load before writing a subtree As part of refactoring the manifest, certain test cases started failing because writesubtrees was called with p1 and p2 manifests that had not been loaded (so accessing m1._dirs resulted in an empty set). Let's call _load on these before attempting to access _dirs. This was caught by tests when future patches were applied.

histedit: correct output of error when 'base' is from the edit list This was made more obvious by marmoute's recent rearrangement of this code.

py3: split check of pygments-using files from the rest of the tree If we don't do this, people without pygments installed in their Python 3 environment silently stop checking test-check-py3-compat, which isn't really what we wanted. This preserves stability of the test output while still letting anyone with a recent-enough Python 3 run the majority of the Python 3 compat checking test.

version: change "place" field of extension to "bundled" flag The name "place" sounds odd. We can simply expose raw boolean values instead of switching external/internal literals.

extensions: use ismoduleinternal() thoroughly "ships-with-hg-core" would be long enough to typo.