Add support for showing/hiding the colon

Allow showing or hiding the colon separator via a lambda call.
Also update the README

components/ht16k33_alpha/README.md

@@ -1,4 +1,6 @@
-# HT16K33 4 character alphanumeric display
+# HT16K33 4 character display
+
+This component supports both the 4 character 14 segment alphanumeric display and the 4 character (plus colon) 7 segment character display. Use the `type` parameter to select which kind of display you have.
 
 There are no print functions for addressing rows and columns.  With such a small display I didn't see any point.
 All the print functions without the row and column parameters are available.
@@ -7,14 +9,17 @@ All the same parameters for the i2c display can be used other than the dimension
 There are also lambda functions `get_brightness` and `set_brightness` for adjusting the brightness of the display.
 You can extend the display across multiple units.
 
+For the 7-segment displays with colon, there is also the `show_colon` lambda function, that can be used to select whether the colon between the second and third digits should be lit or not.
+
 Example:
 ```yaml
-i2c:    
+i2c:
   sda: D0
   scl: D1
 
 display:
   - platform: ht16k33_alpha
+    type: alpha
     address: 0x70
     scroll: true
     scroll_speed: 250ms
@@ -25,6 +30,9 @@ display:
     secondary_displays:
       - address: 0x71
 ```
+# Required parameters
+
+`type:` choose between `alpha` or `7segment`, depending on which kind of display you have
 
 # Optional parameters
 

components/ht16k33_alpha/ht16k33_display.cpp

@@ -62,12 +62,11 @@ void HT16K337SegmentDisplay::display_() {
   constexpr uint8_t size = 10;
   uint8_t buffer[size];
   memcpy(buffer, this->buffer_ + offset, 4);
-// TODO: implement method to show/hide colon symbol
-//  if (this->show_colon()) {
-//    buffer[4] = 0x02;
-//  } else {
+  if (this->show_colon_) {
+    buffer[4] = 0x02;
+  } else {
     buffer[4] = 0;
-//  }
+  }
   buffer[5] = 0;
   memcpy(buffer + 6, this->buffer_ + offset + 4, 4);
 

components/ht16k33_alpha/ht16k33_display.h

@@ -40,6 +40,8 @@ class HT16K33BaseDisplay : public PollingComponent, public i2c::I2CDevice {
   void strftime(const char *format, ESPTime time) __attribute__((format(strftime, 2, 0)));
 #endif
 
+  void show_colon(bool show) { this->show_colon_ = show; }
+
  protected:
   void command_(uint8_t value);
   void call_writer() { this->writer_(*this); }
@@ -58,6 +60,7 @@ class HT16K33BaseDisplay : public PollingComponent, public i2c::I2CDevice {
   int buffer_fill_ {0};
   int offset_ {0};
   uint8_t brightness_ = 16;
+  bool show_colon_ {false};
 };
 
 class HT16K33AlphaDisplay : public HT16K33BaseDisplay {