Replace two dashes and one whitespace with their corresponding ASCII characters. (#362)

.github/CONTRIBUTING.md

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 11f19a0..46bd0bb 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -23,7 +23,7 @@
 
 When creating a new topic on the forums or filing an issue, please include as many relevant details as possible. Examples include:
 
-* A clear description of the situation — what you observe, what you expect, and your view on how the two differ.
+* A clear description of the situation - what you observe, what you expect, and your view on how the two differ.
 * A reproducible test case or sequence of steps.
 * The version of our code being used.
 * Any modifications you've made relevant to the bug.

include/task.h

diff --git a/include/task.h b/include/task.h
index b1e7b23..92381ea 100644
--- a/include/task.h
+++ b/include/task.h
@@ -2777,7 +2777,7 @@
  *  // spent in the Blocked state does not exceed MAX_TIME_TO_WAIT. This
  *  // continues until either the buffer contains at least uxWantedBytes bytes,
  *  // or the total amount of time spent in the Blocked state reaches
- *  // MAX_TIME_TO_WAIT – at which point the task reads however many bytes are
+ *  // MAX_TIME_TO_WAIT - at which point the task reads however many bytes are
  *  // available up to a maximum of uxWantedBytes.
  *
  *  size_t xUART_Receive( uint8_t *pucBuffer, size_t uxWantedBytes )

portable/GCC/MCF5235/readme.md

diff --git a/portable/GCC/MCF5235/readme.md b/portable/GCC/MCF5235/readme.md
index 650cfcc..ebf6ea6 100644
--- a/portable/GCC/MCF5235/readme.md
+++ b/portable/GCC/MCF5235/readme.md
@@ -1,2 +1,2 @@
-The MCF5235 port is deprecated. The last FreeRTOS version that includes this port is 10.4.3.
+The MCF5235 port is deprecated. The last FreeRTOS version that includes this port is 10.4.3.