Added links to interrupt-based wiki page

src/BuildOpt.h

@@ -953,6 +953,14 @@
   //#define RADIOLIB_RADIOSHIELD
 #endif
 
+/*
+ * Uncomment to enable interrupt-based timing control
+ * For details, see https://github.com/jgromes/RadioLib/wiki/Interrupt-Based-Timing
+ */
+#if !defined(RADIOLIB_INTERRUPT_TIMING)
+  //#define RADIOLIB_INTERRUPT_TIMING
+#endif
+
 /*
  * Uncomment to enable static-only memory management: no dynamic allocation will be performed.
  * Warning: Large static arrays will be created in some methods. It is not advised to send large packets in this mode.

src/protocols/PhysicalLayer/PhysicalLayer.h

@@ -348,6 +348,7 @@ class PhysicalLayer {
 
     /*!
       \brief Set function to be called to set up the timing interrupt.
+      For details, see https://github.com/jgromes/RadioLib/wiki/Interrupt-Based-Timing
 
       \param func Setup function to be called, with one argument (pulse length in microseconds).
     */
@@ -355,6 +356,7 @@ class PhysicalLayer {
 
     /*!
       \brief Set timing interrupt flag.
+      For details, see https://github.com/jgromes/RadioLib/wiki/Interrupt-Based-Timing
     */
     void setTimerFlag();