the proposed changes:
I believe there are some mistakes in the following docstrings:
    1. in Lib/importlib/_bootstrap.py:
        - _module_repr - a typo
        - _exec - I believe 'Execute the module specified by the spec' is more accurate than 'Execute the spec'. 
        This docstring wasn't changed since this version of _exec was added in revision 90915 (this version of _exec replaced the one that was in _SpecMethods), so I guess the exact phrasing of that docstring wasn't already challenged.
        - _find_spec - I believe "Find a module's spec." is more accurate than "Find a module's loader.", as the function returns a spec and not a loader. It might be argued that ultimately the function does find a loader. However, we have the perfectly normal case where it is a namespace package, and _find_spec doesn't find any loader. 
        This docstring was the docstring of _find_module, and was left as is when _find_spec replaced _find_module in revision 87347 (which implemented PEP 451), so I guess the exact phrasing of that docstring (in the context of _find_spec) wasn't already challenged.
    2. in Lib/importlib/_bootstrap_external.py:
        - PathFinder._path_hooks - It seems the function's docstring was left as is when issue #14605 was addressed, and thus, since revision 76566, the docstring is inaccurate. 
        - PathFinder.find_spec - I believe "Try to find a spec for 'fullname' on..." is more accurate than "find the module on..." (I took the phrasing from Doc\library\importlib.rst). 
        It seems this docstring was copied from PathFinder.find_module when it was added in revision 87347, and was never changed since, so I guess its exact phrasing wasn't already challenged. 
        - FileFinder.find_spec - It seems this docstring was copied from FileFinder.find_loader when it was added in revision 87347, and was never changed since. Again, I took the phrasing of my proposed new docstring from Doc\library\importlib.rst.


diff:
The patches diff is attached.


tests:
I played a little with the interpreter, and everything worked as usual. I also verified that CPython was indeed compiled with my patched frozen modules (made by _freeze_importlib.exe), by reading patched docstrings interactively via 'import _frozen_importlib' and 'import _frozen_importlib_external'.

In addition, I run 'python -m test' (on my 64-bit Windows 10) before and after applying the patch, and got quite the same output.
the outputs of both runs are attached.

Thanks for the thorough review, Oren! I'll have a look at the patch when I get a chance.

New changeset d32517de5d8c by Brett Cannon in branch 'default':
Issue #26972: Fix some mistakes in importlib-related docstrings.
https://hg.python.org/cpython/rev/d32517de5d8c

Thanks for the patch, Oren! The only real change I made was to make sure the the one-sentence summary at the start of the docstring fit on a single line (when it spans line it can muck up editors and tools).