Manual: remove nonexisting syntax in “svar_identification”

(cherry picked from commit d9feb045)

doc/manual/source/the-model-file.rst

@@ -12045,7 +12045,6 @@ below.
         UPPER_CHOLESKY;
         LOWER_CHOLESKY;
         EXCLUSION CONSTANTS;
-        EXCLUSION LAG INTEGER; VARIABLE_NAME [,VARIABLE_NAME...];
         EXCLUSION LAG INTEGER; EQUATION INTEGER, VARIABLE_NAME [,VARIABLE_NAME...];
         RESTRICTION EQUATION INTEGER, EXPRESSION = EXPRESSION;