Maint: misc. typos

Found via `codespell`.

Source/cmDocumentationFormatter.cxx

@@ -90,7 +90,7 @@ void cmDocumentationFormatter::SetIndent(const char* indent)
 
 void cmDocumentationFormatter::PrintColumn(std::ostream& os, const char* text)
 {
-  // Print text arranged in an indented column of fixed witdh.
+  // Print text arranged in an indented column of fixed width.
   const char* l = text;
   long column = 0;
   bool newSentence = false;

Source/cmTargetSourcesCommand.cxx

@@ -57,7 +57,7 @@ std::vector<std::string> cmTargetSourcesCommand::ConvertToAbsoluteContent(
   cmTarget* tgt, const std::vector<std::string>& content,
   bool isInterfaceContent)
 {
-  // Skip conversion in case old behavior has been explictly requested
+  // Skip conversion in case old behavior has been explicitly requested
   if (this->Makefile->GetPolicyStatus(cmPolicies::CMP0076) ==
       cmPolicies::OLD) {
     return content;

Source/cmTryCompileCommand.h

@@ -16,7 +16,7 @@ class cmExecutionStatus;
 /** \class cmTryCompileCommand
  * \brief Specifies where to install some files
  *
- * cmTryCompileCommand is used to test if soucre code can be compiled
+ * cmTryCompileCommand is used to test if source code can be compiled
  */
 class cmTryCompileCommand : public cmCoreTryCompile
 {

Source/cmTryRunCommand.h

@@ -16,7 +16,7 @@ class cmExecutionStatus;
 /** \class cmTryRunCommand
  * \brief Specifies where to install some files
  *
- * cmTryRunCommand is used to test if soucre code can be compiled
+ * cmTryRunCommand is used to test if source code can be compiled
  */
 class cmTryRunCommand : public cmCoreTryCompile
 {