Clean up comments in bivariate.h and subexpr.h

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Transurgeon

include/bivariate.h

@@ -42,8 +42,7 @@ expr *new_const_scalar_mult(double a, expr *child);
 /* Constant vector elementwise multiplication: a ∘ f(x) where a is constant */
 expr *new_const_vector_mult(const double *a, expr *child);
 
-/* Left matrix multiplication with parameter source: P @ f(x) where P is a parameter
- */
+/* Left matrix multiplication: P @ f(x) where P is a parameter */
 expr *new_left_param_matmul(expr *param_node, expr *child);
 
 /* Parameter scalar multiplication: p * f(x) where p is a parameter */

include/subexpr.h

@@ -118,8 +118,7 @@ typedef struct left_matmul_expr
     CSR_Matrix *A;
     CSR_Matrix *AT;
     CSC_Matrix *CSC_work;
-    expr *
-        param_source; /* if non-NULL, refresh A/AT values from param_source->value */
+    expr *param_source;
     int src_m, src_n; /* original (non-block-diag) matrix dimensions */
 } left_matmul_expr;