api: Fix typos in comments (all found by codespell)

Signed-off-by: Stefan Weil <sw@weilnetz.de>

api/baseapi.cpp

@@ -1660,7 +1660,7 @@ char* TessBaseAPI::GetUNLVText() {
             word->word->space() > 0 &&
             !word->word->flag(W_FUZZY_NON) &&
             !word->word->flag(W_FUZZY_SP)) {
-          /* Write a space to separate from preceeding good text */
+          /* Write a space to separate from preceding good text */
           *ptr++ = ' ';
           last_char_was_tilde = false;
         }

api/pdfrenderer.cpp

@@ -178,7 +178,7 @@ void TessPDFRenderer::AppendPDFObject(const char *data) {
   AppendString((const char *)data);
 }
 
-// Helper function to prevent us from accidentaly writing
+// Helper function to prevent us from accidentally writing
 // scientific notation to an HOCR or PDF file. Besides, three
 // decimal points are all you really need.
 double prec(double x) {

api/tesseractmain.cpp

@@ -227,7 +227,7 @@ int main(int argc, char **argv) {
   }
 
   // We have 2 possible sources of pagesegmode: a config file and
-  // the command line. For backwards compatability reasons, the
+  // the command line. For backwards compatibility reasons, the
   // default in tesseract is tesseract::PSM_SINGLE_BLOCK, but the
   // default for this program is tesseract::PSM_AUTO. We will let
   // the config file take priority, so the command-line default