Update comments for closer reading of the spec.

Section 2.3.1 is the C0 set, which "is not stored or displayed"
Section 2.3.2 is the C1 set, so interpret "all control characters"
in this context as meaning "all C1 characters".

src/conio/cterm.c

@@ -6480,22 +6480,10 @@ CIOLIBEXPORT size_t cterm_write(struct cterminal * cterm, const void *vbuf, int
 								}
 								else if (buf[j] < 32) {
 									// Unhandled C0 control
-									// Section 2.2:
+									// Section 2.3.1:
 									// "The C0 CHARACTER SET... contain... characters which are not stored or displayed"
-									// Section 2.3.2, HOLD MOSAIC
-									// "Generally all control characters are displayed as spaces"
-#if 0
-									// Section 2.3.2 holds...
-									uctputs(cterm, prn);
-									prn[0]=0;
-									prnpos = prn;
-									// We use 0 here to ensure it's not interpreted
-									// but does get the held mosaic.
-									prestel_handle_escaped(cterm, 0);
-#else
-									// Section 2.2 holds...
+									// Section 2.3.2 appears to be specific to the C1 set
 									/* Do Nothing */
-#endif
 								}
 								else {
 									// G1... unicode replacement