Use consistent language for string termination (#806)

Avoid hyphen, prefer space: "null terminated"

modules/database/src/ioc/db/dbChannel.h

@@ -206,7 +206,7 @@ typedef struct chFilterIf {
      *
      * Optional.
      * \param filter Pointer to instance data.
-     * \param stringVal Value, not zero-terminated.
+     * \param stringVal Value, not null terminated.
      * \param stringLen Number of chars in \p stringVal.
      * \returns \p parse_stop on error, or \p parse_continue
      */
@@ -226,7 +226,7 @@ typedef struct chFilterIf {
      *
      * Optional.
      * \param filter Pointer to instance data.
-     * \param key Value not zero-terminated.
+     * \param key Value not null terminated.
      * \param stringLen Number of chars in \p key
      * \returns \p parse_stop on error, or \p parse_continue
      */

modules/database/src/ioc/db/dbConvert.c

@@ -444,7 +444,7 @@ static long getCharChar(const dbAddr *paddr,
 
     if (paddr->pfldDes && paddr->pfldDes->field_type == DBF_STRING) {
         /* This is a DBF_STRING field being read as a long string.
-         * The buffer we return must be zero-terminated.
+         * The buffer we return must be null terminated.
          */
         pdst[--nRequest] = 0;
         if (nRequest == 0)
@@ -466,7 +466,7 @@ static long getCharUchar(const dbAddr *paddr,
 
     if (paddr->pfldDes && paddr->pfldDes->field_type == DBF_STRING) {
         /* This is a DBF_STRING field being read as a long string.
-         * The buffer we return must be zero-terminated.
+         * The buffer we return must be null terminated.
          */
         pdst[--nRequest] = 0;
         if (nRequest == 0)

modules/database/src/ioc/db/dbLink.h

@@ -111,7 +111,7 @@ typedef struct lset {
     /** @brief  load constant long string from link type
      *
      * Usually called during IOC initialization, constant link types must copy a
-     * nil-terminated string up to size characters long to the buffer provided,
+     * null terminated string up to size characters long to the buffer provided,
      * and write the length of that string to the plen location. A non-constant
      * link type can use this as an early hint that subsequent calls to
      * dbGetLink() will request long string data, although this might change.