i18n: Add support for translating the class reference

- Parse `.po` files from `doc/translations/*.po` like already done
  with `editor/translations/*.po`.
- Add logic to register a doc translation mapping in `TranslationServer`
  and `EditorSettings`.
- Add `DTR()` to lookup the doc translation mapping (similar to `TTR()`).
  Strings are automatically dedented and stripped of whitespace to ensure
  that they would match the translation catalog.
- Use `DTR()` to translate relevant strings in `EditorHelp`,
  `EditorInspector`, `CreateDialog`, `ConnectionsDialog`.
- Small simplification to `TranslationLoaderPO`, the path argument was
  not really meaningful.

2 files changed, 8 insertions, 8 deletions

diff --git a/core/io/translation_loader_po.cpp b/core/io/translation_loader_po.cpp
index 4051bf2947..f1d3f19b58 100644
--- a/core/io/translation_loader_po.cpp
+++ b/core/io/translation_loader_po.cpp
@@ -33,7 +33,7 @@
 #include "core/os/file_access.h"
 #include "core/translation.h"
 
-RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const String &p_path) {
+RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error) {
 
 	enum Status {
 
@@ -67,7 +67,7 @@ RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const S
 
 			if (status == STATUS_READING_ID) {
 				memdelete(f);
-				ERR_FAIL_V_MSG(RES(), p_path + ":" + itos(line) + " Unexpected EOF while reading 'msgid' at file: ");
+				ERR_FAIL_V_MSG(RES(), f->get_path() + ":" + itos(line) + " Unexpected EOF while reading 'msgid' at file: ");
 			} else {
 				break;
 			}
@@ -78,7 +78,7 @@ RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const S
 			if (status == STATUS_READING_ID) {
 
 				memdelete(f);
-				ERR_FAIL_V_MSG(RES(), p_path + ":" + itos(line) + " Unexpected 'msgid', was expecting 'msgstr' while parsing: ");
+				ERR_FAIL_V_MSG(RES(), f->get_path() + ":" + itos(line) + " Unexpected 'msgid', was expecting 'msgstr' while parsing: ");
 			}
 
 			if (msg_id != "") {
@@ -100,7 +100,7 @@ RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const S
 			if (status != STATUS_READING_ID) {
 
 				memdelete(f);
-				ERR_FAIL_V_MSG(RES(), p_path + ":" + itos(line) + " Unexpected 'msgstr', was expecting 'msgid' while parsing: ");
+				ERR_FAIL_V_MSG(RES(), f->get_path() + ":" + itos(line) + " Unexpected 'msgstr', was expecting 'msgid' while parsing: ");
 			}
 
 			l = l.substr(6, l.length()).strip_edges();
@@ -115,7 +115,7 @@ RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const S
 			continue; //nothing to read or comment
 		}
 
-		ERR_FAIL_COND_V_MSG(!l.begins_with("\"") || status == STATUS_NONE, RES(), p_path + ":" + itos(line) + " Invalid line '" + l + "' while parsing: ");
+		ERR_FAIL_COND_V_MSG(!l.begins_with("\"") || status == STATUS_NONE, RES(), f->get_path() + ":" + itos(line) + " Invalid line '" + l + "' while parsing: ");
 
 		l = l.substr(1, l.length());
 		//find final quote
@@ -128,7 +128,7 @@ RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const S
 			}
 		}
 
-		ERR_FAIL_COND_V_MSG(end_pos == -1, RES(), p_path + ":" + itos(line) + " Expected '\"' at end of message while parsing file: ");
+		ERR_FAIL_COND_V_MSG(end_pos == -1, RES(), f->get_path() + ":" + itos(line) + " Expected '\"' at end of message while parsing file: ");
 
 		l = l.substr(0, end_pos);
 		l = l.c_unescape();
@@ -153,7 +153,7 @@ RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error, const S
 			config = msg_str;
 	}
 
-	ERR_FAIL_COND_V_MSG(config == "", RES(), "No config found in file: " + p_path + ".");
+	ERR_FAIL_COND_V_MSG(config == "", RES(), "No config found in file: " + f->get_path() + ".");
 
 	Vector<String> configs = config.split("\n");
 	for (int i = 0; i < configs.size(); i++) {
diff --git a/core/io/translation_loader_po.h b/core/io/translation_loader_po.h
index fe3a75e5eb..d280729e94 100644
--- a/core/io/translation_loader_po.h
+++ b/core/io/translation_loader_po.h
@@ -37,7 +37,7 @@
 
 class TranslationLoaderPO : public ResourceFormatLoader {
 public:
-	static RES load_translation(FileAccess *f, Error *r_error, const String &p_path = String());
+	static RES load_translation(FileAccess *f, Error *r_error = NULL);
 	virtual RES load(const String &p_path, const String &p_original_path = "", Error *r_error = NULL, bool p_use_sub_threads = false, float *r_progress = nullptr);
 	virtual void get_recognized_extensions(List<String> *p_extensions) const;
 	virtual bool handles_type(const String &p_type) const;