GHA/checksrc: expand spellcheck, fix issues found

- codespell: break logic out into its own runnable script. Allowing
  to run it on local machines.
- codespell: install via `pip`, bump to latest version.
- codespell: show version number in CI log.
- codespell: drop no longer needed word exception: `msdos`.
- codespell: include all curl source tree, except `packages` and
  `winbuild`. Drop an obsolete file exclusion.
- add new spellchecker job using the `typos` tool. It includes
  the codespell dictionary and a couple more. Use linuxbrew to install
  it. This takes 10 seconds, while installing via `cargo` from source
  would take over a minute.
- codespell: introduce an inline ignore filter compatible with `cspell`
  Make `typos` recognize it, too. Move single exceptions inline.

Fix new typos found. Also rename variables and words to keep
spellchecking exceptions at minumum. This involves touching some tests.
Also switch base64 strings to `%b64[]` to avoid false positives.

Ref: https://github.com/crate-ci/typos/blob/master/docs/reference.md
Ref: https://github.com/codespell-project/codespell?tab=readme-ov-file#inline-ignore
Ref: https://github.com/codespell-project/codespell/issues/1212#issuecomment-1721152455
Ref: https://cspell.org/docs/Configuration/document-settings

Closes #17905

docs/examples/adddocsref.pl

@@ -36,9 +36,9 @@ for $f (@ARGV) {
             # just ignore preciously added refs
         }
         elsif($l =~ /^( *).*curl_easy_setopt\([^,]*, *([^ ,]*) *,/) {
-            my ($prefix, $anc) = ($1, $2);
-            $anc =~ s/_//g;
-            print NEW "$prefix/* $docroot/curl_easy_setopt.html#$anc */\n";
+            my ($prefix, $anchor) = ($1, $2);
+            $anchor =~ s/_//g;
+            print NEW "$prefix/* $docroot/curl_easy_setopt.html#$anchor */\n";
             print NEW $l;
         }
         elsif($l =~ /^( *).*(curl_([^\(]*))\(/) {

docs/examples/cacertinmem.c

@@ -41,7 +41,7 @@ static size_t writefunction(void *ptr, size_t size, size_t nmemb, void *stream)
   return nmemb * size;
 }
 
-static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
+static CURLcode sslctx_function(CURL *curl, void *sslctx, void *pointer)
 {
   CURLcode rv = CURLE_ABORTED_BY_CALLBACK;
 
@@ -93,8 +93,9 @@ static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
   X509_STORE  *cts = SSL_CTX_get_cert_store((SSL_CTX *)sslctx);
   int i;
   STACK_OF(X509_INFO) *inf;
-  (void)curl;
-  (void)parm;
+
+  (void)curl; /* avoid warnings */
+  (void)pointer; /* avoid warnings */
 
   if(!cts || !cbio) {
     return rv;

docs/examples/ftpuploadfrommem.c

@@ -31,7 +31,7 @@
 
 static const char data[]=
   "Lorem ipsum dolor sit amet, consectetur adipiscing elit. "
-  "Nam rhoncus odio id venenatis volutpat. Vestibulum dapibus "
+  "___ rhoncus odio id venenatis volutpat. Vestibulum dapibus "
   "bibendum ullamcorper. Maecenas finibus elit augue, vel "
   "condimentum odio maximus nec. In hac habitasse platea dictumst. "
   "Vestibulum vel dolor et turpis rutrum finibus ac at nulla. "

docs/examples/httpput-postfields.c

@@ -33,7 +33,7 @@ static const char olivertwist[]=
   "Among other public buildings in a certain town, which for many reasons "
   "it will be prudent to refrain from mentioning, and to which I will assign "
   "no fictitious name, there is one anciently common to most towns, great or "
-  "small: to wit, a workhouse; and in this workhouse was born; on a day and "
+  "small: to ___, a workhouse; and in this workhouse was born; on a day and "
   "date which I need not trouble myself to repeat, inasmuch as it can be of "
   "no possible consequence to the reader, in this stage of the business at "
   "all events; the item of mortality whose name is prefixed";

docs/examples/post-callback.c

@@ -33,9 +33,9 @@
 static const char data[]="Lorem ipsum dolor sit amet, consectetur adipiscing "
   "elit. Sed vel urna neque. Ut quis leo metus. Quisque eleifend, ex at "
   "laoreet rhoncus, odio ipsum semper metus, at tempus ante urna in mauris. "
-  "Suspendisse ornare tempor venenatis. Ut dui neque, pellentesque a varius "
+  "Suspendisse ornare tempor venenatis. Ut dui neque, pellentesque a ______ "
   "eget, mattis vitae ligula. Fusce ut pharetra est. Ut ullamcorper mi ac "
-  "sollicitudin semper. Praesent sit amet tellus varius, posuere nulla non, "
+  "sollicitudin semper. Praesent sit amet tellus ______, posuere nulla non, "
   "rhoncus ipsum.";
 
 struct WriteThis {

docs/examples/simplessl.c

@@ -66,7 +66,7 @@ int main(void)
 #ifdef USE_ENGINE
   pKeyName  = "rsa_test";
   pKeyType  = "ENG";
-  pEngine   = "chil";            /* for nChiper HSM... */
+  pEngine   = "chil";            /* for nCipher HSM... */
 #else
   pKeyName  = "testkey.pem";
   pKeyType  = "PEM";

docs/examples/usercertinmem.c

@@ -51,7 +51,7 @@ static size_t writefunction(void *ptr, size_t size, size_t nmemb, void *stream)
   return nmemb * size;
 }
 
-static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
+static CURLcode sslctx_function(CURL *curl, void *sslctx, void *pointer)
 {
   X509 *cert = NULL;
   BIO *bio = NULL;
@@ -124,7 +124,7 @@ static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
     "-----END RSA PRIVATE KEY-----\n";
 
   (void)curl; /* avoid warnings */
-  (void)parm; /* avoid warnings */
+  (void)pointer; /* avoid warnings */
 
   /* get a BIO */
   bio = BIO_new_mem_buf((char *)mypem, -1);