8177078: jshell tool: fix documentation of /help shortcuts

8177735: jshell tool: /help /help -- typo "comand"
8177308: jshell tool: documentation: multiple start-up files and predefines not documented

Reviewed-by: jlahoda

langtools/src/jdk.jshell/share/classes/jdk/internal/jshell/tool/resources/l10n.properties

@@ -97,7 +97,10 @@ Or type one of the following commands:\n
 jshell.msg.help.subject =\n\
 For more information type ''/help'' followed by the name of a\n\
 command or a subject.\n\
-For example ''/help /list'' or ''/help intro''.  Subjects:\n
+For example ''/help /list'' or ''/help intro''.\n\
+\n\
+Subjects:\n\
+\n
 
 jshell.err.drop.arg =\
 In the /drop argument, please specify an import, variable, method, or class to drop.\n\
@@ -403,7 +406,7 @@ Display information about jshell.\n\
 /help\n\t\
      List the jshell commands and help subjects.\n\n\
 /help <command>\n\t\
-     Display information about the specified comand. The slash must be included.\n\t\
+     Display information about the specified command. The slash must be included.\n\t\
      Only the first few letters of the command are needed -- if more than one\n\t\
      each will be displayed.  Example:  /help /li\n\n\
 /help <subject>\n\t\
@@ -444,7 +447,7 @@ Display information about jshell (abbreviation for /help).\n\
 /?\n\t\
      Display list of commands and help subjects.\n\
 /? <command>\n\t\
-     Display information about the specified comand. The slash must be included.\n\t\
+     Display information about the specified command. The slash must be included.\n\t\
      Only the first few letters of the command are needed -- if more than one\n\t\
      match, each will be displayed.  Example:  /? /li\n\
 /? <subject>\n\t\
@@ -478,7 +481,8 @@ control what you are doing, like:  /list\n\
 \n\
 For a list of commands: /help
 
-help.shortcuts.summary = a description of shortcuts
+help.shortcuts.summary = a description of keystrokes for snippet and command completion,\n\
+information access, and automatic code generation
 help.shortcuts =\
 Supported shortcuts include:\n\
 \n\
@@ -791,7 +795,7 @@ The form without <command> or options shows the editor setting.\n
 help.set.start =\
 Set the start-up configuration -- a sequence of snippets and commands read at start-up:\n\
 \n\t\
-/set start [-retain] <file>\n\
+/set start [-retain] <file>...\n\
 \n\t\
 /set start [-retain] -default\n\
 \n\t\
@@ -806,9 +810,9 @@ Show the start-up setting:\n\
 /set start\n\
 \n\
 The contents of the specified <file> become the start-up snippets and commands used\n\
-when the /reset or /reload commands are used in this session.\n\
-If instead the -default option is specified, the predefined start-up snippets\n\
-will be used.\n\
+when the /reset, /reload, or /env commands are used in this session.\n\
+If instead the -default option is specified, the predefined start-up import\n\
+snippets will be used.\n\
 If the -none option is used, the start-up will be empty -- no start-up snippets\n\
 or commands will be used.\n\
 This command is good for testing the start-up settings.  To retain them for future\n\
@@ -820,7 +824,16 @@ runs of the jshell tool.\n\
 \n\
 The form without <file> or options shows the start-up setting.\n\
 Note: if the start-up was last set from a file, this is shown with the\n\
-contents of the file followed by a 'set start' command.
+'set start' command followed by the contents of the file.\n\
+\n\
+The <file> may be an operating system file name, or one of the predefined\n\
+startup file names: DEFAULT, PRINTING, or JAVASE.\n\
+These are respectively: the default import snippets (as used by -default),\n\
+definitions of print(), println(), and printf() method snippets, or\n\
+imports of all Java SE packages.\n\
+More than one <file> may be specified, for example:\n\
+\n\t\
+/set start -retain DEFAULT PRINTING
 
 startup.feedback = \
 /set mode verbose -command    \n\