Trac #31032: some raw string for pdf doc building in sage-on-gentoo

BAck in sage 9.1 we had issues with building pdf docs because of missing
raw strings.

Some issues that were also happening in vanilla sage have been fixed and
merged but sage-on-gentoo continued to carry a few extra ones.

This ticket is to merge those leftovers.

URL: https://trac.sagemath.org/31032
Reported by: fbissey
Ticket author(s): François Bissey
Reviewer(s): Frédéric Chapoton

Author: Release Manager

src/sage/categories/pushout.py

@@ -1146,7 +1146,7 @@ def _repr_(self):
 
 
 class InfinitePolynomialFunctor(ConstructionFunctor):
-    """
+    r"""
     A Construction Functor for Infinite Polynomial Rings (see :mod:`~sage.rings.polynomial.infinite_polynomial_ring`).
 
     AUTHOR:
@@ -1187,7 +1187,7 @@ class InfinitePolynomialFunctor(ConstructionFunctor):
         ...
         CoercionException: Incompatible term orders lex, degrevlex
 
-    In an infinite polynomial ring with generator `a_\\ast`, the variable `a_3` will always be greater
+    In an infinite polynomial ring with generator `a_\ast`, the variable `a_3` will always be greater
     than the variable `a_1`. Hence, the orders are incompatible in the next example as well::
 
         sage: A.construction()[0]*PolynomialRing(QQ,names=['x','y','a_1','a_3'], order='lex').construction()[0]
@@ -1197,7 +1197,7 @@ class InfinitePolynomialFunctor(ConstructionFunctor):
 
     Another requirement is that after merging the order of the remaining variables must be unique.
     This is not the case in the following example, since it is not clear whether the variables `x,y`
-    should be greater or smaller than the variables `b_\\ast`::
+    should be greater or smaller than the variables `b_\ast`::
 
         sage: A.construction()[0]*PolynomialRing(QQ,names=['a_3','a_1','x','y'], order='lex').construction()[0]
         Traceback (most recent call last):
@@ -1215,7 +1215,7 @@ class InfinitePolynomialFunctor(ConstructionFunctor):
         sage: X.<w,x,y> = InfinitePolynomialRing(ZZ)
         sage: Y.<x,y,z> = InfinitePolynomialRing(QQ)
 
-    `X` and `Y` have an overlapping generators `x_\\ast, y_\\ast`. Since the default lexicographic order is
+    `X` and `Y` have an overlapping generators `x_\ast, y_\ast`. Since the default lexicographic order is
     used in both rings, it gives rise to isomorphic sub-monoids in both `X` and `Y`. They are merged in the
     pushout, which also yields a common parent for doing arithmetic::
 

src/sage/rings/polynomial/infinite_polynomial_element.py

@@ -1285,7 +1285,7 @@ def reduce(self, I, tailreduce=False, report=None):
 
     ## Further methods
     def stretch(self, k):
-        """
+        r"""
         Stretch ``self`` by a given factor.
 
         INPUT:
@@ -1294,7 +1294,7 @@ def stretch(self, k):
 
         OUTPUT:
 
-        Replace `v_n` with `v_{n\\cdot k}` for all generators `v_\\ast` occurring in self.
+        Replace `v_n` with `v_{n\cdot k}` for all generators `v_\ast` occurring in self.
 
         EXAMPLES::
 

src/sage/rings/polynomial/infinite_polynomial_ring.py

@@ -1,4 +1,4 @@
-"""
+r"""
 Infinite Polynomial Rings
 
 By Infinite Polynomial Rings, we mean polynomial rings in a countably
@@ -10,8 +10,8 @@
 - Simon King <[email protected]>
 - Mike Hansen <[email protected]>
 
-An Infinite Polynomial Ring has finitely many generators `x_\\ast,
-y_\\ast,...` and infinitely many variables of the form `x_0, x_1, x_2,
+An Infinite Polynomial Ring has finitely many generators `x_\ast,
+y_\ast,...` and infinitely many variables of the form `x_0, x_1, x_2,
 ..., y_0, y_1, y_2,...,...`.  We refer to the natural number `n` as
 the *index* of the variable `x_n`.
 
@@ -619,10 +619,10 @@ def __getitem__(self, k):
 ##  The sparse implementation
 
 class InfinitePolynomialRing_sparse(CommutativeRing):
-    """
+    r"""
     Sparse implementation of Infinite Polynomial Rings.
 
-    An Infinite Polynomial Ring with generators `x_\\ast, y_\\ast,
+    An Infinite Polynomial Ring with generators `x_\ast, y_\ast,
     ...` over a field `F` is a free commutative `F`-algebra generated
     by `x_0, x_1, x_2, ..., y_0, y_1, y_2, ..., ...` and is equipped
     with a permutation action on the generators, namely `x_n^P =