pwm.hpp: fixed some typos and styling in comments

Signed-off-by: Alex Tereschenko <alext.mkrs@gmail.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/pwm.hpp

@@ -46,9 +46,9 @@ class Pwm
      *
      * @param pin the pin number used on your board
      * @param owner if you are the owner of the pin the destructor will
-     * @param chipid the pwmchip to use, use only in raw mode
      * unexport the pin from sysfs, default behaviour is you are the owner
      * if the pinmapper exported it
+     * @param chipid the pwmchip to use, use only in raw mode
      */
     Pwm(int pin, bool owner = true, int chipid = -1)
     {
@@ -77,7 +77,7 @@ class Pwm
      * Set the output duty-cycle percentage, as a float
      *
      * @param percentage A floating-point value representing percentage of
-     * output. The value should lie between 0.0f (representing on 0%) and
+     * output. The value should lie between 0.0f (representing 0%) and
      * 1.0f Values above or below this range will be set at either 0.0f or
      * 1.0f
      * @return Result of operation
@@ -91,7 +91,7 @@ class Pwm
      * Read the output duty-cycle percentage, as a float
      *
      * @return A floating-point value representing percentage of
-     * output. The value should lie between 0.0f (representing on 0%) and
+     * output. The value should lie between 0.0f (representing 0%) and
      * 1.0f Values above or below this range will be set at either 0.0f or
      * 1.0f
      */
@@ -134,7 +134,7 @@ class Pwm
         return (Result) mraa_pwm_period_us(m_pwm, us);
     }
     /**
-     * Set pulsewidth, As represnted by seconds in a (float)
+     * Set pulsewidth, as represented by seconds in a float
      *
      * @param seconds The duration of a pulse
      * @return Result of operation
@@ -179,9 +179,9 @@ class Pwm
         return (Result) mraa_pwm_enable(m_pwm, enable);
     }
     /**
-     * Get the maximum pwm period in us
+     * Get the maximum PWM period in us
      *
-     * @return max pwm in us
+     * @return max PWM period in us
      */
     int
     max_period()
@@ -189,9 +189,9 @@ class Pwm
         return mraa_pwm_get_max_period(m_pwm);
     }
     /**
-     * Get the minimum pwm period in us
+     * Get the minimum PWM period in us
      *
-     * @return min pwm in us
+     * @return min PWM period in us
      */
     int
     min_period()