Fix docstring formatting to use raw string literals in multiple files

Discovered via pytest, which follows stricter rules when parsing doctests.

Author: tobiasdiez

src/sage/algebras/free_algebra_quotient_element.py

@@ -142,7 +142,7 @@ def _repr_(self):
             return repr_lincomb(zip(mons, cffs), strip_one=True)
 
     def _latex_(self):
-        """
+        r"""
         EXAMPLES::
 
             sage: H, (i,j,k) = sage.algebras.free_algebra_quotient.hamilton_quatalg(QQ)

src/sage/algebras/lie_algebras/bgg_dual_module.py

@@ -172,7 +172,7 @@ def _repr_generator(self, m):
         return self._module._repr_generator(m) + "^*"
 
     def _latex_generator(self, m):
-        """
+        r"""
         Return a latex representation of the generator indexed by ``m``.
 
         EXAMPLES::

src/sage/algebras/steenrod/steenrod_algebra_misc.py

@@ -567,7 +567,7 @@ def normalize_profile(profile, precision=None, truncation_type='auto', p=2, gene
 
 
 def milnor_mono_to_string(mono, latex=False, generic=False):
-    """
+    r"""
     String representation of element of the Milnor basis.
 
     This is used by the _repr_ and _latex_ methods.
@@ -720,7 +720,7 @@ def serre_cartan_mono_to_string(mono, latex=False, generic=False):
 
 
 def wood_mono_to_string(mono, latex=False):
-    """
+    r"""
     String representation of element of Wood's Y and Z bases.
 
     This is used by the _repr_ and _latex_ methods.
@@ -806,7 +806,7 @@ def wall_mono_to_string(mono, latex=False):
 
 
 def wall_long_mono_to_string(mono, latex=False):
-    """
+    r"""
     Alternate string representation of element of Wall's basis.
 
     This is used by the _repr_ and _latex_ methods.
@@ -891,7 +891,7 @@ def arnonA_mono_to_string(mono, latex=False, p=2):
 
 
 def arnonA_long_mono_to_string(mono, latex=False, p=2):
-    """
+    r"""
     Alternate string representation of element of Arnon's A basis.
 
     This is used by the _repr_ and _latex_ methods.

src/sage/misc/inline_fortran.py

@@ -12,7 +12,7 @@
 
 
 def _import_module_from_path(name, path=None):
-    """
+    r"""
     Import the module named ``name`` by searching the given path entries (or
     `sys.path` by default).