This patch introduces line continuation based indent for triple strings,
which typically span multiple lines without any explicit newlines in the
syntax tree (since they are hidden inside the string).
This result in the following changes, some of which are clearly
bugfixes:
Operator chains:
```diff
"""
abc
""" * """
-def
-"""
+ def
+ """
```
Operator chain as assignment right hand side:
```diff
x = """
-abc
-""" * """
-def
-"""
+ abc
+ """ * """
+ def
+ """
```
Implicit tuples:
```diff
"""
abc
""",
"""
-def
-"""
+ def
+ """
```
Note that single triple strings as a right hand side is excluded from
the indent rule, similar to having `if/try/let/...` blocks as a right
hand side.
Fredrik Ekre
af1b7377f4