Fix constant folding of multiplied string literals when they appear in another constant expression. In this case, the multiplied value was lost and replaced by the original value.

Try to call "__rmod__()" during string %-formatting when the right side is a string subtype that implements it.
See https://bugs.python.org/issue28598

Fix constant folding of multiplied string literals when they appear in another constant expression. In this case, the multiplied value was lost and replaced by the original value.

cython_inline compiler directives support

Support two-element slicing with literal None

Closes #2587.

Simplify encoding detection and source file opening by starting off reading bytes, and only switching to decoding once we know which encoding to use.