LaTeX: revert in index entries to \textbar{} not \sphinxtextbar{}

This is because of case of an index directive or role in a table cell.
For the same reason tabulary is not compatible with code-cells,
it affects index entries. The escaping of | char by a LaTeX macro
needed to be by a "robus" or "protected" one, or by string like {"|}.
This was not the choice of previous commit, by oversight.

By reverting to \textbar{} (which is a "robust" command) we also
maintain maximal backwards compatibility for the sorting in the
index done by the makeindex program.

sphinx/texinputs/sphinx.sty

@@ -1881,10 +1881,9 @@
     \let\sphinxtermref  \@firstofone
 }}
 
-% For curly braces and vertical bar inside \index macro
+% For curly braces inside \index macro
 \def\sphinxleftcurlybrace{\{}
 \def\sphinxrightcurlybrace{\}}
-\def\sphinxverticalbar{|}
 
 % Declare Unicode characters used by linux tree command to pdflatex utf8/utf8x
 \def\spx@bd#1#2{%

sphinx/texinputs/sphinx.xdy

@@ -109,7 +109,6 @@
 
 (merge-rule "\sphinxleftcurlybrace{}" "{" :string)
 (merge-rule "\sphinxrightcurlybrace{}" "}" :string)
-(merge-rule "\sphinxverticalbar{}" "|" :string)
 (merge-rule "\_" "_" :string)
 (merge-rule "{[}" "[" :string)
 (merge-rule "{]}" "]" :string)
@@ -127,6 +126,7 @@
 (merge-rule "\(\rightarrow\)" "→" :string)
 (merge-rule "\(\checkmark\)" "✓" :string)
 (merge-rule "\textendash{}" "–" :string)
+(merge-rule "\textbar{}" "|" :string)
 (merge-rule "\(\sp{\text{0}}\)" "⁰" :string)
 (merge-rule "\(\sp{\text{1}}\)" "¹" :string)
 (merge-rule "\(\sp{\text{2}}\)" "²" :string)

sphinx/writers/latex.py

@@ -1816,7 +1816,7 @@ class LaTeXTranslator(SphinxTranslator):
             value = value.replace('"', '""')
             value = value.replace('@', '"@')
             value = value.replace('!', '"!')
-            value = value.replace('|', r'\sphinxverticalbar{}')
+            value = value.replace('|', r'\textbar{}')
             return value
 
         def style(string):