tidy-up: OS names

Use these words and casing more consistently across text, comments and
one curl tool output:
AIX, ALPN, ANSI, BSD, Cygwin, Darwin, FreeBSD, GitHub, HP-UX, Linux,
macOS, MS-DOS, MSYS, MinGW, NTLM, POSIX, Solaris, UNIX, Unix, Unicode,
WINE, WebDAV, Win32, winbind, WinIDN, Windows, Windows CE, Winsock.

Mostly OS names and a few more.

Also a couple of other minor text fixups.

Closes #14360

docs/examples/anyauthput.c

@@ -100,7 +100,7 @@ int main(int argc, char **argv)
   fp = fopen(file, "rb");
   fstat(FILENO(fp), &file_info);
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   curl_global_init(CURL_GLOBAL_ALL);
 
   /* get a curl handle */

docs/examples/ephiperfifo.c

@@ -33,7 +33,7 @@
  *
  * Written by Jeff Pohlmeyer, converted to use epoll by Josh Bialkowski
 
-Requires a linux system with epoll
+Requires a Linux system with epoll
 
 When running, the program creates the named pipe "hiper.fifo"
 

docs/examples/ftpgetresp.c

@@ -48,17 +48,17 @@ int main(void)
   FILE *respfile;
 
   /* local filename to store the file as */
-  ftpfile = fopen(FTPBODY, "wb"); /* b is binary, needed on win32 */
+  ftpfile = fopen(FTPBODY, "wb"); /* b is binary, needed on Windows */
 
   /* local filename to store the FTP server's response lines in */
-  respfile = fopen(FTPHEADERS, "wb"); /* b is binary, needed on win32 */
+  respfile = fopen(FTPHEADERS, "wb"); /* b is binary, needed on Windows */
 
   curl = curl_easy_init();
   if(curl) {
     /* Get a file listing from sunet */
     curl_easy_setopt(curl, CURLOPT_URL, "ftp://ftp.example.com/");
     curl_easy_setopt(curl, CURLOPT_WRITEDATA, ftpfile);
-    /* If you intend to use this on windows with a libcurl DLL, you must use
+    /* If you intend to use this on Windows with a libcurl DLL, you must use
        CURLOPT_WRITEFUNCTION as well */
     curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, write_response);
     curl_easy_setopt(curl, CURLOPT_HEADERDATA, respfile);

docs/examples/ftpupload.c

@@ -90,7 +90,7 @@ int main(void)
   /* get a FILE * of the same file */
   hd_src = fopen(LOCAL_FILE, "rb");
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   curl_global_init(CURL_GLOBAL_ALL);
 
   /* get a curl handle */

docs/examples/ftpuploadfrommem.c

@@ -76,7 +76,7 @@ int main(void)
   upload.readptr = data;
   upload.sizeleft = strlen(data);
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   res = curl_global_init(CURL_GLOBAL_DEFAULT);
   /* Check for errors */
   if(res != CURLE_OK) {

docs/examples/http-post.c

@@ -33,7 +33,7 @@ int main(void)
   CURL *curl;
   CURLcode res;
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   curl_global_init(CURL_GLOBAL_ALL);
 
   /* get a curl handle */

docs/examples/http2-upload.c

@@ -32,7 +32,7 @@
 #include <sys/stat.h>
 #include <errno.h>
 
-/* somewhat unix-specific */
+/* somewhat Unix-specific */
 #ifndef _MSC_VER
 #include <sys/time.h>
 #include <unistd.h>

docs/examples/httpput-postfields.c

@@ -58,7 +58,7 @@ int main(int argc, char **argv)
 
   url = argv[1];
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   curl_global_init(CURL_GLOBAL_ALL);
 
   /* get a curl handle */

docs/examples/httpput.c

@@ -82,7 +82,7 @@ int main(int argc, char **argv)
      an example! */
   hd_src = fopen(file, "rb");
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   curl_global_init(CURL_GLOBAL_ALL);
 
   /* get a curl handle */

docs/examples/multi-legacy.c

@@ -30,7 +30,7 @@
 #include <stdio.h>
 #include <string.h>
 
-/* somewhat unix-specific */
+/* somewhat Unix-specific */
 #ifndef _WIN32
 #include <sys/time.h>
 #include <unistd.h>

docs/examples/post-callback.c

@@ -73,7 +73,7 @@ int main(void)
   wt.readptr = data;
   wt.sizeleft = strlen(data);
 
-  /* In windows, this inits the winsock stuff */
+  /* In Windows, this inits the Winsock stuff */
   res = curl_global_init(CURL_GLOBAL_DEFAULT);
   /* Check for errors */
   if(res != CURLE_OK) {

docs/examples/unixsocket.c

@@ -22,7 +22,7 @@
  *
  ***************************************************************************/
 /* <DESC>
- * Access HTTP server over unix domain socket
+ * Access HTTP server over Unix domain socket
  * </DESC>
  */
 #include <stdio.h>